texts: Derivation of ripple factor equation for a full-wave rectifier with filter

texts:
I'm trying to derive the ripple factor for a full wave rectifier with a filter.

This parameter is defined as the ratio of the root mean square (rms) value of the ripple voltage (Vr_rms) to the absolute value of the DC component of the output voltage:

γ =  Vr_rms / Vdc

I use the following plot with an assumption of |AB| = T/2.

First I want to write an expression for ripple rms voltage Vr_rms.

The ripple amplitude as seen in the plot is Vr. This can be approximated(using Taylor series expansion's first term for exponential decay) and given for full wave rectifier with a filter as:

Vr = |XY| = t/τ * Vm, and in this case t = T/2 and τ = R*C

Vr = Vm / (2*CRf) and rms value of a triangle wave is given as Vp/sqrt(3) so:

Vr_rms = Vm / (2*sqrt(3)xCRf)

Now I want to find the average DC voltage Vdc. This can be approximated as:

Vdc = Vm - (Vr/2)

This yields the ripple factor:

γ =  Vr_rms / Vdc

γ  = [Vm / (2*sqrt(3)xCRf) ] / [Vm - (Vr/2)]

γ  = [1 / (2*sqrt(3)xCRf) ] / [1 - (Vr/(2*Vm))] and since Vr/Vm = 1/(2*CRf)

γ = [1 / (2*sqrt(3)xCRf) ] / [1 - (1/(4*CRf))]

I'm stuck at this point I cannot progress and the texts give this factor as:

How is this derived? I cannot reach this..


texts: How to multiply a very slow clock (1 kHz) into MHz range

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I have an RS485 network connecting several MCU boards where communication happens in 1ms intervals. With the MCU it's therefore easy to create a 1kHz clock with approx 50% duty cycle using the counters. I want to multiply this 1kHz frequency to about 40 MHz needed for the CLKIN of an ADC. What I'm trying to achieve is to keep the ADC running in continuous mode, delivering one sample per ms without the boards drifting apart.
I looked at various PLL ICs but they expect input frequencies in the MHz range.
In case this is impossible or impractical, I will run the ADC in single shot mode, but I'm curious if it's possible at all.
Topology: There are 10 devices on an RS485 bus running at 1 MHz spanning about 10 meters. One of them is the master who initiates communication every 1ms. The other 9 devices derive their 1kHz clock from those communications.
Clock source: The master divides its MCU clock to approx. 1kHz via a counter. In the counter ISR the master initiates the transfer of the sync-byte via the UART.
Clock derivation: After receiving the sync byte from the master, the slaves (in their UART ISR) take a pin - let's call it CLKout - to high. They start a one shot timer who will take CLKout low after about 0.5ms.
If the slaves are a few microseconds out of phase it's no problem.


texts: STM32 I2C Read Variable Length message from Slave

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I have two devices that must communicate over I2C. The master writes some data to the slave, and then it must read back a response from the slave.

Neither the slave nor the master knows the length of the message that should be received. On the Slave this is not a problem, I set the DMA to receive 255 bytes (more than the master will ever write in one message), and then wait for the STOP condition to be raised to signal the end of the transfer.

On the Master I can't figure out how to read a message from the slave without knowing how many bytes should be read. Is there a way to do this? My understanding is that the Master generates the STOP condition, so I can't use that.

I currently just read back one byte from the slave that contains the number of bytes that are to be transferred, and then do another read for that amount of data, but I am looking for a more efficient and faster way.

I am using STM32L433 MCU's and have used the LL-Libraries for the I2C code with DMA to transfer the messages to the peripheral.
Best Regards


texts: Measuring electro-hydraulic drive's inertia

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I have an electro-hydraulic drive – a hydraulic motor with coupled to it a synchronous generator. Also there is an encoder installed on the shaft of the generator. By using my DAQ unit I will measure its position, speed and acceleration. The most important aspect for me right now is how I can measure the drive’s inertia and be as precise as possible.

I now that Torque = Inertia * Acc. Acceleration can be measured by the DAQ. But what to do with the drive’s torque? I can agree that the hydraulic motor’s torque can be calculated (I know pressure, displacement and its efficiency). There is no electrical connection of the generator to an exciter or means, so it is literally only extra load on the motor’s shaft. In this case I am just wondering, can I actually use the motor's torque as the drive's torque (motor plus generator).

So in this case, I can use the derived motor’s torque and measured acceleration in order to calculate the inertia? Is something wrong with my approach or?


texts:
I have a motor that's rated at 28A.
I want to monitor the power it's drawing so I got an ACS712 in its 30A variant. Knowing the voltage and multiplying by the output I get the power.
But what happens if the motor is stalled for whatever reason and the current goes above the supposed maximum of the ACS712? I tried to find some information about that in the datasheet but all that was stated regarding the measured current was a maximum transient of 100A for 100ms, which doesn't say quite a lot (at least to me).
Is the sensor going to be destroyed or is it just going to output the maximum regardless of how much above that the real current is?


texts: How are the terminal voltages regulated for this Wheatstone bridge?

texts:
At page 34 from this datasheet the following circuit shows a single-ended amplifier used to produce single-ended gain:

As you see the excitation voltage terminals is sensed by Kelvin connection method as REF+ and REF-.

By why are these terminals sensed in this case? Normally they should be sensed to regulate the excitation voltage but in this case I cannot see any feedback circuit. Are the REF+ and REF- signals really used to regulate the excitation terminals voltages in this circuit?


texts: how to calculate the maximum power transfer? (specific exercise example included)

texts:
I have a hard time figuring out how to calculate the maximum power transfer.. Can anyone help?
I understand that you need to calculate the thevenin resistance by killing the sources and summing the individual resistances, but I'm unsure about the next few steps and formulars to follow.

Edit:
After reading through the comments saying I should show more effort, I've tried to apply KCL at the three independent nodes and solving the equations for the unknown variables using wordmat: V_a, V_b, V_c. Assuming V_c is equal to the open circuit voltage V_oc, I've then used V_oc along with the calculated thevenin resistance in the maximum power transfer equation: P_max = V_oc^2 / 4*R_th.
However, I've most likely calculated V_oc wrongly.. Anyone who could tell me what I did wrong in my calculations?
btw, I accidentally mistyped the unit for V_c, which should be in volts.


texts: Design a circuit that would turn off output between two input voltage levels

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The circuits for the three stages of input voltage can be drawn easily, but I am confused about how to make the circuit "identify" the voltages.

For eg, How can I turn off output exactly between -3V and +5V.
Please help me out!


texts: Help finding multiple feedback (MFB) high-pass filter design formulas?

texts:
I can't seem to find some easily code-able formulas for MFB high pass filter. I have found plenty for the low pass filter, but absolutely none for the high pass filter. For example, the formulas on page 7 for the low pass:
https://www.ti.com/lit/an/sloa049b/sloa049b.pdf?ts=1606593846769&ref_url=https%253A%252F%252Fwww.google.com%252F
they have broken the transfer function into Q, gain, and cutoff frequency. This is exactly what I am looking for, but for the high pass transfer function. The ones that I have come across look like this, page 2: https://www.analog.com/media/ru/training-seminars/tutorials/mt-220.pdf
Here, I don't even know what alpha is in terms of components, and there is no expression for Q. I also don't understand the significance of k. Or worse, I run into this on page 310: http://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf The use of the a1 and b1 coefficients here makes it much harder to code.
Should be a pretty easy question, I am just looking for design formulas for the MFB high-pass filter that mirror those from the TI link at the beginning. And yes, I have used Analogs filter wizard, I am doing this to recalculate the component values that I have designed there.


texts: Why does connecting batteries in series result in doubled current sourcing while shorting?

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I have Duracell Ultra Power AAA batteries, current draw is around 2.5A when shorting for single unit.

I have just tried connecting them in series and parallel then measure discharge current.

Results:

Parallel: A bit increased current sourcing
Series: doubled current sourcing

It doesn't make sense if we think in terms of V=IR since series connection also increase internal resistance.

So my question is why? I doubt battery chemistry is the limiting parameter not the internal resistance ( maybe it is low enough?)

(BTW my end goal is to use 2 AA batteries to step up to 3.6V while supplying 2A for short bursts)


texts: High current, low voltage (~10v area) supply from standard 220v/10A outlet

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I have a few brushless motors and some ESCs (Electronic speed controllers) which expects a 2 or 3 cell LiPo battery. For testing purposes I would like to have a power supply that can drive the motors - with the ESCs - so that I don't need to charge the batteries all the time.

I need 7.4v (2 cell) or 11.1v (3 cell) and it would be great to have 10A+. I want to keep down price, so can I make one myself?


texts:
Can you explain about microphone preamplifier in the next circuit?

http://circuitndiagram.blogspot.ru/2013/04/fm-transmitter.html

Is this mic preamplifier of class C? If it is then how can it works?  Will I hear the sound?
I just can't understand  why we can use class C amplifier instead A?


texts: Phase shift in AC Circuit power calculation

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I have the below question. I am not trying to ask the answer for the problem.

But my question is that, we can see that 60deg is the phase shift.
But both the voltage and current across the passive element is 60deg. With respect to what is the phase shift 60deg.
Is the phase shift 60deg is with respect to AC Voltage source? Or is it with respect to what?
And for the power calculation, I should just multiply the values of V and I.


texts: LT1711 maximum supply voltage and maximum input voltage

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I want to include the LT17111 comparator into my design but I cannot get some clear information from the datasheet here.

Can I power it from 12V and GND?
Can I put a signal with 8V amplitude into one of its inputs?

Thank you!


texts: Difference between wire wound and ceramic chip inductors

texts: I have two boxes of SMD r.f. inductors. One lot are wire wound, and the others are ceramic chip. What is the difference in construction? From peering at them with a microscope I see that the wire wound ones are, umm, wound with wire. But how are the ceramic chip ones made? What do they look like inside? I notice that the \$Q\$ for the wire wound ones is higher. Are there any other important differences in usage?


texts: Charge 18650 with BCAP0050 2.7V 50F is possible?

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my first question is!

I need to charge a 18650 with two BCAP0050 2.7V 50F

My question is... Is it possible?

Thanks in advanced!


texts: Opto-coupler output photo-transistor as normal BJT

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I am currently using a 4N49 opto for command isolation (no speed requirements, just isolation for a slow 64ms signal). There is different section of the design which also needs a NPN transistor switch. Would there be any issues, if I use the output phototransistor as a normal BJT switch. (ignore the ground connections and part values, couldnt find the 4N49 in circuit lab). SPICE simulations work fine, will try on the breadboard

simulate this circuit – Schematic created using CircuitLab
I have verified this in spice with the schematic below.


texts: Electronic load for negative voltage PSU

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I am making a MOSFET based electronic load to test my PSU rails.
Below is a simplified version of my circuit with V2 as the PSU that is being tested. I want to be able to test negative voltage rails too, which must share a common ground with the supply voltage (V1).

Is there some way to simply modify this type of design to allow for negative voltages to be loaded?

thanks!

simulate this circuit – Schematic created using CircuitLab


texts: Resistance as reference in impedance triangle

texts: Why Resistance is taken as reference in impedance triangle of RL series circuit, why not reactance as reference ?


texts: Atmel Xmega ADC input voltage range - Can the ADC be damaged by exceeding it's reference voltage, if the input is still less then VCC?

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I've been working with Atmels ATxmega parts a lot recently, and there is one question I still have that I have not been able to find a answer to, even after scouring the datasheets.

Basically, The ADC in the xmega series are somewhat limited by the fact that the \$V_{REF}\$ cannot exceed \$V_{CC}-0.6V\$. This is easily enough accommodated, I am using a 2.048V reference for the ADC with 3.3V rails.

However, I cannot determine if exceeding the ADC \$V_{REF}\$ on the ADC inputs would be actually harmful to the device.

I'm aware exceeding the \$V_{REF}\$ will saturate the ADC, this is fine in this application. However, having to clamp the input to \$V_{REF}\$ would be challenging in my application, as the \$V_{REF}\$ I'm using cannot sink any current, so if I simply used a simple schottky diode to clamp \$V_{in}\$ to \$V_{REF}\$, any excursions of \$V_{in}\$ would simply cause \$V_{REF}\$ to rise as well. I'd really prefer not to have to add a whole additional buffer just to accommodate potential occasional \$V_{in}\$ excursions.

Looking through the datasheet, I'm not really much enlightened:

The ADC IO lines are "Pin"s, so I would assume that exceeding the reference, as long as the voltage is kept < \$V_{CC}\$, while the conversion results may be invalid, it won't cause actual damage to the MCU.

On the other hand:

Note that this isn't specified as an "Absolute Maximum" value. I'm not sure if this implies that exceeding these bounds will lead to invalid conversion results, or actual damage.

I've been through both the part-specific datasheet (ATxmega32e5 in this case), and the E series databook, and neither have clarified the issue much for me.


texts:
I'm looking at the article posted here, and I'm trying to figure out what it is that they're controlling and how.
Specifically, Dave Wilson from TI gave a presentation called "Teaching Old Motors New Tricks" and has posted the slides as well.  In this PDF on page 9, he gets into the work required to implement the observer.  Basically, you implement the transfer function of the motor, feed in the voltage into your model, calculate the currents that would be coming out of it, and compare that to the actual current measurements....That error goes into a PI loop and smashes the error to zero...What's left over must be the BEMF.  Then, that signal (from both the alpha and beta channels) are fed into a beat-frequency generator (also in the code) to extract angle information, similar to how a resolver works.

That's fine, but I want to use the algorithm that's posted in the first link's research paper because I have some C code as a reference that already implements it.  I just don't understand what/how they're using what they can measure as well as what they know about the motor beforehand (flux-linkage, for instance) to infer the angle of the rotor.

Any help in decoding that paper would be greatly appreciated.  Also, if you have time, how do they calculate flux linkage?  I found this post here that states that the flux linkage is

  lambda = 60 / (sqrt(3) * pi * kv * pole_num)

but this seems hand-wavy to me.


texts: Switching 9V using a NPN transistor and an Arduino

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First of all, I'd like to say I'm not an Electrical engineer so please bear with me. I haven't got a sketch for what I'm trying to achieve but hopefully I can explain it ok.

I have an NPN transistor (2n2222 specifically) and am doing the following.

Connect 9V battery to transistor collector
Connect transistor base to Arduino PWM output pin (1k transistor in between)
Connect ground of 9V battery to Arduino ground
Write a for loop (i = 0-255) which increments by 1 every 100ms and do analogWrite(PWMOutputPin, i)

I then take a multimeter to measure the voltage between ground and the emitter leg and what I'm getting is values between 0-4.5 volts while the battery has about 7.68V in it by measuring it directly.

I thought the purpose of the transistor is to send the full voltage between the collector and emitter provided that there's sufficient voltage being sent to the base. Is this correct? Am I doing something wrong?


texts: How can I set the input signal to LTspice with equal intervals?

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In transient analysis I define a voltage input such as a square wave input and obtain an output voltage. Here I set the input signal:

Export time series:

But when I export the input and export time series signals from LTspice as a text, the time points do not have equal intervals. From the text file time plotted:

Is it possible to set it so we have an input and output with equal time intervals? Such as a sampled input and output with a constant sampling rate fs.


texts: How to write 4 bytes continuous data without any SCK delay through SPI with Pic18f45k20

texts: In pic18f45k20, I have to write 4byte data at once without any setup SCK delay through SPI. Is there any way to cancel the SCK delay while sending 4 bytes together?(like Assembly)I am using MPLAB-XC8 and hitech c. In 10Mhz SPI, I got 460ns SCK delay between two bytes. However, I would like to cancel that delay to write 4byte data at once.


texts: Diodes used with MOV, which ones and why?

texts:
i was hoping to get some help identifying a component on an old circuit board that i have to repair, id also like to undertand the purpose of this combination of components.

The circuit is on an industrial plasma cutter from 1988 , this circuit runs at about 250-300v dc @ 40-80 Amps, it runs between the 3 phase rectifiers and the ssr

in short the 3phase supply goes through the transformer, into the recitiers on the  left edge of the photo, it then passes through this circuit and goes into the ssr on the top edge of the photo, the full voltage is 300v 80 amp dc, drops to around 250v under load, as this is an inductive load from the transformer, and is being switched by pwm controlled ssr, and it this circuit mostly consists of mov's i assume its purpose will be to prevent transient voltage spikes from switching under load, what i dont know is what type or rating these diodes are.
could someone assist me with identifying them and tell me what specs i should be replacing them with?


texts: How to size coupling and bypass capacitor for simple BJT CE stage

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I'm a new user in this forum and I want ask you a question about a simple CE BJT stage design.
I want to know,if possible, a procedure design for sizing coupling and bypass capacitor for following circuit

After sized R1,R2,Rc,Re for gain specifics and bias ,how to size C1,C2 and C3 for a low cut frequency?What is analytic procedure or way of thinking for sizing them?Thanks


texts:
I recently discovered a project to program PIC18Fs with an Arduino here: https://sites.google.com/site/thehighspark/arduino-pic18f

All other ICSP PIC programmers I've seen are more complicated than just 4 resistors. This might just be because this project does not support high voltage programming. Is this an OK circuit to use to program PICs, or is it possible the programming will error out, or worse yet, the PIC burns out?


texts: How can I control a LED with two separate control circuits?

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I have a LED controlled by a microcontroller.

I want to know how I can bypass this microcontroller so that I can control the LED with a separate current. Would I use transistors to switch between the two controllers to prevent backflow damage to my microcontroller? If so how?


texts: What special considerations and/or constraints are typically applied when routing analog video signals on a PCB (e.g. VGA, NTSC, etc). I'm thinking try and keep them routed on a single layer (i.e. at most 2 vias), try and keep a ground plane under the tracks, and minimize the number of other (digital) signals that cross over those tracks, match the lengths of the R, G, B, and Syncs to within a couple hundred mils. What I'm really asking, is what kinds of formal constraints do people use in Electrical CAD tools when dealing with Analog video signals?


texts: How can line code polarity inversion happen?

texts:
One of the disadvantages of some line codes like NRZ-L or RZ is that if a sudden change in polarity occurs, then all received bits will be erroneous (flipped).

How can such a sudden change in polarity occur in practice?
And is it really a problem?


texts:
Is the flyback diode adequate protection in for the microcontroller in the following circuit?

simulate this circuit – Schematic created using CircuitLab

Will my circuit experience over voltage conditions on the 5V rail despite the flyback diode? My 5V is generated by a step-down switching regulator if that matters, and that switcher circuit has a 220uF capacitor on it's LX node.


texts: Can an analog inductive proximity sensor be used to discriminate between different types of metal (aluminum and steel)?

texts:
I am attempting to create a robot that will sort aluminum from steel automatically via an arduino.  The code is essentially: if steel, do X, if aluminum, then do Y.

I am using an analog inductive proximity sensor (NPN) made by IFM (product page here).

I have managed to read values from the sensor with analogRead, but the values for aluminum and steel are exactly the same (around 165).  I am using the arduino's native INPUT_PULLUP function since the sensor is sinking.

I am using a 27 volt power source (3x 9 volt batteries) sent through a voltage regulator set to output 25 volts.

How can discrimination be achieved? is this even possible with the current hardware?    I was lead to believe that this was possible, but I am not very experienced.

Thanks

EDIT: I purchased this sensor believing that it was an analog sensor, but it is not.


texts: Trans-conductance amplifier using CS MOS amplifier

texts:
What is the meaning of the text "Less control on input Impedance"?
Why did we add CS amplifier for this purpose?


texts: How reliable is it to use another manufacturer's datasheet of the same part?

texts:
There is a part, 1N4148, or whatever from manufacturer A, but the datasheet from manufacturer B is more detailed, has nice graphs, etc.

Is in general data for the exact part consistent between manufacturers?


texts:
Currently I'm working on the design of 1st stage of CMOS differential amp (pic. 1). I'm using classical design to achieve at least some gain. I'm using CMOS 90nm process and SPECTRE simulator.

So far output for typical simulation is something like this (Output of simulation. Red = IN, cyrene = out.):

Also outputs are color coded on schematic
This schematic should work even with input common mode equals zero, so in simulation vin_common = 0 and vinp is grounded.
Typical RS = 200K, but I tried numbers from 1K to 300K
I tried to change W/L of transistors, and so far they seem picked reasonably, but there is still no gain in case of any W/L ratios. What's wrong with the design, or with it's W/L ratios?
P.S. As you asked here is some characteristics of MOSFETS:


texts: Why do I see multiple waveforms on my oscilloscope in normal trigger mode?

texts:
I have two I2C messages 20 ms apart:

When I adjust the horizontal scale and look at them in normal trigger mode, I see both of them overlayed over each other:

(At least that is what I assume I'm seeing.)

After the second message there's silence for a second or so, so this image stays on screen until the next transmission.

If I press the RUN/STOP button, I see just one message:

Display persistence is off. Is this a bug in my Rigol DS1052E or do I have some misconception about how normal trigger mode works? If the trigger holdoff time is short enough for the second message to trigger again, shouldn't the first message be cleared from the screen before recording the second one?


texts: How are equations (transfer functions) and the uncertainties for sensors found?

texts:
Does anyone have a good: book / link / resource which describes from the ground up how to find an equation / transfer function and the accompanying uncertainties for sensors?
I am looking for references for my bachelor's thesis and want to understand it better myself, what the approach is when designing a sensor how to find the transfer function and calculate the uncertainties.
With my limited knowledge, I understand an equation / transfer function has to be found which describes the sensor Input and Output. This can be done by calibrating the sensor with a lookup table and curve fitting.
This is my approach to calculate the transfer function of my sensor:
I have a self made pressure (force) sensor which changes its resistance based on exerted force. It acts like a variable resistor. I have measured the resistance of the sensor 5 times at forces from 1 to 10 N, using a digital multimeter. Then I calculated the average resistance at each force level (AVG in the 1st table.)
These averages I graphed, and let Excel make a power function trendline to describe the AVG data. The function and R^2 value is displayed on the graph.
Then to calculate uncertainty:
In the last table I calculated the MAPE (mean average percent error.) Here under "theoretical resistance" are the calculated resistances from the trendline power equation at each force value. I compared the original AVG resistances to this theoretical power function and below are the calculated MAPE and MAE error values.
Is my sensor uncertainty thus the power equation +/- this MAPE of AVG vs theoretical?

R = 2008,1*F^(-0,871)  +/- 8,2 %  ?


texts: How much current Hold and WP SPI Flash pins can draw?

texts:
In my design J14 is used as header to which I connect wires to an external programmer (DediProg) in order to program an SPI Flash (U25).
At the time of flashing, I don't want to supply voltage to (3V3AUX) gives power to a Host Controller which needs this flash ROM for functioning properly.
I want to use BAT54WS Schottky diode in order not to supply 3V3AUX voltage at the time the DediProg programmer is ON (VCC_DEDIPROG is high) and supplying voltage:

I'm using PM25LV080B Flash and I was wondering if the flash can draw so much current, in a way that the voltage on the diode would be too high such that the remained voltage would not be enough for the SPI flash to stay working.
According to the table and datasheet, there is no information about how much current WP# and HOLD# pins can draw. I only know that VCC draws up tp 30 mA.
at 30mA the voltage drop on the diode would around 500mV, which would leave 3.1V for the flash VCC. how do I know that the WP# and HOLD# pins don't pull the VCC voltage below 2.7v which is below the working range?


texts: how to find transfer function of this filter

texts:
how can i find the trans. function of this circuit , is there any way to find the total impedance , i don't want to use Laplace transform .
and can i find the bode diagram for this circuit ?


texts:
I am making a trailer to pull behind my 26" bike. I am wanting to run a bottle dynamo off of each of the trailer tires and charge 1-2 car batteries off of them which will power my light setup as well as phone charger, speakers and various other electronics that I may desire. The trailer, besides being my on the go power source, is all intended to be a mobile power station.

I play a location based game similar to Pokemon go and we have gatherings where we get together and play in a localized area and would like to be able to drop the trailer, with the batteries charged, and have everyone be able to plug in and charge their devices/battery packs then show up later and hook back up to ride off and recharge.

What I need to know is what I need to put between the dynamos and the battery and also what I need between the battery and the usb hub that will distribute the power to all the electronics.

Have also been considering adding a motor to power the wheel so that I can relax some over my longer distance rides(generally ride a minimum of 10-20 miles one way). Had considered finding a gas powered motor designed for a bike but have since come to consider an electric motor, which from my understanding should be able to be wired directly from the battery though if someone has a reason that won't work please feel free to say so.


texts: What defines the maximum primary current of a (sensor-only) current transformer?

texts:
Take the Coilcraft CS1200L for example, which states the sensed current maximum is 35 A.

This limit doesn't seem to be defined by the wire size which can fit through the hole (5 mm) as you can pass > 100A of current through a 5 mm wire.

It also doesn't appear to be limited by saturation in the transformer core. Using the calculator provided by coilcraft with 35 A sensed current, 25 kHz input frequency, 50% duty cycle and 1 V output, it calculates \$B_{max}=67\$ Gauss. Coilcraft state to stay below 2000 Gauss to avoid saturation so we've got a way to go before hitting that limit.

I found a reference discussing the 53200C which states "The maximum current of 10A within the rated bandwidth of this product is a thermal limit". This implies power dissipation is the limiting factor, at least for the 53200C.

I calculated is heating of the secondary from the DC resistance. Using a primary current of 35 A and DCR max of 4.5 Ohms, the losses are \$P=I^2R=\left(\frac{35}{200}\right)^2\cdot4.5=0.138\mathrm{W}\$. That doesn't seem like that much power. There's also hysteresis losses to consider, which should also be low due to the core material and low maximum magnetic flux density. I assume there must be more losses that I'm missing?

On the topic, what allows the CST206-2A to handle 80A RMS rather than the 35A of the CS1200L? It appears to have a slightly lower inductance and DCR max, and a much higher volt-time product.


texts: Is it bad to have sharp bends in an internal data cable?

texts:
I found this in a review of an external SATA HDD enclosure:

  STUPID connection method to hard drive. EVERYONE that has some savvy
  in the computer tech world knows, you don't make sharp turns in data
  cables, or run power cables over data cables. Sharp bends reduce data
  speed, and power cables over data cables causes "cross talk", causing
  data integrity issues.

Are these valid complaints?


texts:
I'm attempting to source replacement batteries for some medical devices (digital goniometer, inclinometer, etc.) The markings are:

GMB063048 3.7V 800mAh 2.0WH 2010.12.08 R

I've found batteries of suitable size and capacity (6mm x 30mm x 48mm, 850mAh). My issue is that the OEM batteries have a 3rd blue lead attached to a thermistor that is connected to a charging circuit on the main PCB.

All of the batteries I've been able to locate have only 2 leads.  I find myself ignorant and frustrated here.  Will I need to order a 2-lead battery and then simply connect the thermistor to the negative terminal in order to make this work, or is there a search term that I'm missing (being ignorant of battery configurations and features) that will help me locate what I'm looking for?

Thanks in advance for your advice and knowledge. I was raised by an electrical engineer, and consider myself an advanced hobbyist.  I know very little about batteries, though.

My plan is to keep the existing thermistor and reuse it on a replacement LiPo cell.  If it's too much trouble to explain why that's a terrible idea (if indeed it is), then a pointer to a resource I can use to teach myself the pertinent details would be fantastic.


texts:
Can you help me with this problem?

what is V(t) before t=0 ?
And also, any hints on how to solve the problem.
This is not homework. I'm studying for a final exam and I'm really stuck. So if anyone could give me the whole solution for one of the circuits, I would be very thankful.


texts: Possible outcomes of not using a current limiting resistor in this LED driver?

texts:
I have this LED Driver in my hand.
I would like to run my LEDs at the maximum brightness possible - meaning I am thinking of excluding the R_EXT (current limiting resistor pin) connection to a resistor.

The datasheet (page 18) doesn't say much other than

The recommended minimum value of REXT is 18kΩ, or
it may cause a large current.

So I don't know if it is ok or not. Will I hear high pitched noise because the driver is over-driven? Will it kill my IC and possibly LEDs in the long term?


texts: Where is load-leveling data stored on a MicroSD card?

texts: Reading this question on load-leveling of writes on a MicroSD card, Is it true that a SD/MMC Card does wear levelling with its own controller?, it prompted me to wonder where on the MicroSD card is this load-leveling data stored?  Is it kept in permanent memory outside of the normal memory storage space?  Or is it kept in a partition table and if I reformat the MicroSD card, will the load-leveling data be deleted?


texts:
How to determine the life expectancy for the given mosfet?

Mosfet : IRFP460

Mosfet Datasheet
http://www.vishay.com/docs/91237/91237.pdf

Actual Voltage,Current and other specification.

Vds = 180VDc

VGS = 12V

Idc = 10A

Mosfet Die temp = 90.C

Switching Freq = 10Khz

Duty cycle = 70% max


texts:
If a rectangle loop would move inside a magnetic field, would the induced ϵ be zero?

Why would it? Is it due to the induced ϵ canceling out? Being in series and in opposition?

If it we're a single wire it would have an induced ϵ = −vBL.


texts:
I'm searching for a -simple- charging circuit for a 3.3 mF 100 V capacitor details here.
The input voltage is 60~80VDC.
Any suggestions?
Edit #1
If I connect the cap directly with no charging circuit, it draws a lot of current which make the fuse of our power supply to switch off the supply. We limit the current to 2 Amperes and the fuse disconnects the supply. Maximum current supported by the circuit before this capacitor is 250mA, so I want to limit the charging current below that level


texts: For the problem shown above since there is no current travelling through the input of the Op-Amp can we assume that the Op-Amp is acting ideally? And using this assumption can we ignore the output resistances as well as A_0?


texts:
I need to control an LED driver with analog 0(1)-10V control input.

This control device should be very cheap and compact so until now I made a schematic which uses the fact that those drivers have 100 uA current source at its dimming input. Switching capacitor made this cheap, small and relatively easy.

But now I need to adapt this solution for a driver which has "400...550 uA current at control pin". This is a problem for several reasons:

I need to drive about 5...10-times more current in the primary circuit which becomes 4-5 mA (I don't have so much current)
Switching capacitance schematic gives a voltage depending on a current. So if this current isn't precise - my voltage will be not precise as well

I'd like to avoid any isolated DC-DC with opamps solutions as this will be big and expensive.

Is there any better solutions?


texts: How do I make an unsigned 8 bit adder in VHDL ? And an unsigned 8 bit subtractor?

texts:
How do I make an unsigned 8 bit adder in VHDL ? And an unsigned 8 bit subtractor  ?
I am having trouble with the unsigned.
The name of the file is adder1.vhd.
I attempt to synthesize it using Design Compiler.
Code is here:
-------------------------------------------------
LIBRARY ieee;
USE ieee.std_logic_1164.all;
--USE ieee.std_logic_arith.all;
use ieee.numeric_std.all;
------------------------------------------------
ENTITY signed_adder IS
PORT (a, b: IN STD_LOGIC_VECTOR(7 DOWNTO 0);
sum: OUT STD_LOGIC_VECTOR(7 DOWNTO 0));
END ENTITY;
------------------------------------------------
ARCHITECTURE arch OF signed_adder IS
SIGNAL a_sig, b_sig: UNSIGNED(3 DOWNTO 0);
BEGIN
a_sig <= UNSIGNED(a);
b_sig <= UNSIGNED(b);
sum <= STD_LOGIC_VECTOR(a_sig + b_sig);
END ARCHITECTURE;

Design Compiler gives me the error....
Error: Cannot find the design 'adder1' in the library 'WORK'. (LBR-0)
0
if { ! $ok } {
  echo "ERROR: elaboration failed"
  exit 1
}
ERROR: elaboration failed

Again, the name is the file compiled is adder1.vhd.
So why is Design Compiler giving me this error ?


texts: High-speed IC GND next to oscillator GND

texts:
I am designing a board, 4 layer with a ground plane. In my current layout, the ground VIA of an oscillator IC is very close in proximity with the ground VIA of a high speed IC. Is there a chance that the returning currents of the high speed IC going to affect the oscillator?
Edit:
The two ICs are on opposite sides of the PCB, the oscillator is on the bottom, high speed IC is on top. The ground plane is closer to top layer.


texts: Create circuit from current–voltage characteristic

texts:
I'm trying to create a circuit from a given current–voltage characteristic like this:

I want to use ideal diodes/ideal voltage source/ideal current source

So my idea was for the dotted graph the left circuit and for the solid graph the right circuit

(in case you wonder I created it with https://www.circuitlab.com)

Is that the right track - and if not what do I need to do then?


texts:
I am trying to identify a component on a board of my roller shutter remote control.

Here is the board:

The main component is very likely the one top-right, identified by x1.

I've tried to find what kind of components are labelled x without success. so I am unable to know what type of transmitter it is. I have referenced How to Read a Schematic

Googling any of the reference I could find on the board did not help either.

Could you help me find resources to be able to identify this?

Edit:
I am interested in this component to understand how I could build a similar control for all my roller shutters and control them via a computer (for instance my raspberrypi).


texts: Most cost effective 6 layer stack setup?

texts:
I've been trying to come up with a 6 layer PCB layout with microvias. But I cannot think of a cost optimized layer stack, because every manufacturer seems to tell me something different on their website. Since I'm quite confused I hope, someone can shed light on this.

Cost is always the driving factor. Thus, production steps have to be kept at a mimimum. My way of thinking went like this:

We have 6 layers, so we have to press 2 times anyway.
Let's name those layers: TO, TC, TI, BI, BC, BO (Top/Bottom Outer/Center/Inner)
Drilling before the first production step seems to be unneccessary, so buried vias from TI to BI are not an option.
Drilling is unneccessary for the inner layers. Microvias are laserdrilled and therefore much smaller and faster.
This results in using microvias from:

TO to TC
TC to TI
BI to BC
BC to BO

The final drilling and electroplating is done anyway, so Through Vias from TO to BO are okay too.

Is this the correct way of thinking and therefore the cost optimized layerstack for this kind of problem (given the given information and assuming standard production methods)? If not, which is?

If we take the cost of (1.) into account and not use all-through vias, how will this alter the cost structure?

Thinking about another possibility: Laser drilling from TO to TC AND TI. Is this a cost-viable option?


texts: LCD panels used in projectors - What are their limitations?

texts:
It's important I point out immediately that I am an absolute novice at all this. I am trying to self-teach myself the basics by building things but it is a slow slow process. So please bear with me if my questions come across dumb.

I am currently learning how projectors work and decided to look at LCD projectors first as opposed to DLP (DMD) as they appeared to be far more complicated.

My question is this:

With the LCD panels being used in these projectors (3 of them), what are their limitations in terms of light?

Are the panels adjusted based off the lumens output from the light in the projector or is it more a "one size fits all" scenario and no matter how much light you shine through the LCD panel, it will produce the same image, just much brighter or dimmer?

Thanks in advance!


texts:
Extremely simple question for you. Probably beneath all of you to answer apologies for that. My camera's flash is rated in Watt seconds.  My battery is rated in mAh .

If my battery can output 1000 milliamp hours and outputs at 110 Volts. And my camera flash draws 100 Watt seconds per fire. Assuming there are no other variables and it's a perfect system, how many camera flashes could I fire.


texts: Why isn't fast decay mode on an h bridge damaging

texts:
I'm struggling to understand how fast decay mode works on an h-bridge used for stepper motors . Particularly I've been looking at fast decay mode in this data sheet: http://www.ti.com/lit/an/slva321/slva321.pdf

What I'm struggling to understand is why when BH and AL are turned on, this doesn't cause damage due to the voltage that the motor coil would wind up putting out as the magnetic field collapsed. As far as I can understand it if we take V(motor-coil) = L * (change in current) / (change in time) if we have a stepper motor coil that is holding at 1A and then we start a step therefore switching which transistors are one, and say we turn off our transistors in 10ns (I just grabbed that from a random transistor datasheet) then wouldn't the voltage across the motor coil wind up being:

V(mc) = L * (0-1) / .000000001

V(mc) = L * -1000000000

So even if the inductance is something really small like 3 mH (taken from random NEMA 17 pololou data sheet) that would still cause a few thousand volt difference across the coil no?

If I look at the diagrams from that data sheet linked above, wouldn't that voltage be applied directly to the input voltage source and ground?

How does this not cause arcing or damage to components that may be up or down stream of this h bridge?


texts:
I'm designing a device that have will play mp3 files either from an internal usb flash drive  (not physically accessible to end user) or from an usb flash drive plugged on an external usb port

Also, there will be times where the external usb port will be used to access the internal usb drive
Basically there are three situations:
1. Playing from internal drive
2. Playing from external drive
3. Using external port to access internal drive

In other words, there are two switches that must be done:
The mp3 engine to switch between internal and external drives
The external port to switch between mp3 engine and internal drive

Any ideas on how to do this switching?
I know of ts3usb30 that can implement one switch to two possible routes. I thought of arrange three of them so that I could achieve the three ways but don't know if it would work.

Any other idea?


texts: Mysterious LEDs glowing in spike buster without switching on

texts:
I have a spike buster at my hostel to power my laptop charger, monitor, phone chargers etc... It has a Line Indication system which shows the status of the supply using 3 LEDs.

Under the "All Ok" condition, only the 1st and 3rd LEDs are supposed to glow. They do that just fine. When it is powered off and the plug is removed from the socket all the lights go out (they can't run on their own). But, when the plug is inserted and the switch is not turned on yet, a strange thing happens. A few LEDs light up! I haven't:

Turned on the switch
Connected any devices (this doesn't seem to change the output)

Slow motion video for the switched ON state : YouTube Link

Slow motion video for the switched OFF state: YouTube Link

What could possibly be the reason behind this?

NOTE - Our hostel has a really poor power supply. There's a lot of fluctuation. I have observed the voltages change from 185V to 220V within a few seconds. There can probably be a lot of harmonics in the power supply due to the usage of lots of SMPS (a laptop charger for each and every one of 400 students!) Could this have anything to do with my situation?


texts:
I'm trying to setup UART communication with the STM32F0 Discovery Board but I am having difficulty adapting the Rx side of things to my needs.

The STM32 will be receiving a message (4-6 bytes with no end character) from the UART device every few seconds and then must send a reply.

How should I be handling receiving messages so that I'm not limited to a fixed message size, so that I don't need to look for an end character (maybe using a timer) and so that glitches don't throw off my entire communications?

I'm debugging the below code with an FTDI USB-UART cable right now and the interrupt only triggers for the first character I send through terminal and then wont trigger again.

//This function handles USART1 global interrupt request.
void USART1_IRQHandler(void)
{
  if( USART_GetITStatus(PMIC_COM1, USART_IT_RXNE))
  {
    char t = USART_ReceiveData(PMIC_COM1);

    //Check if received character is end character
    if( (t != 'x') && (cnt < MAX_STRLEN) ){
      received_string[cnt] = t;
      cnt++;
    }
    else{ // otherwise reset the character counter and print the received string
      cnt = 0;
      printf("UART Message: %c", received_string);
    }
  }
}


texts: Since there is a current in the circuit, supermesh is much preferred. However, how do I do that as the current source is not in between 2 loops? Do I just open circuit at the current source and I will be left with just right and upper loops?


texts:
I am using a LEM HAIS 200-P and I never have worked with Open Loop current sensors before.

I have some questions about the datasheet:

What is the difference between Primary nominal RMS current and
Primary current measuring range?
If I can force some Vref, so how's the offset fixed? It will change
as I force the Vref, right?


texts:
I have got two power supply options on my board:

USB 5.0V
DC Power Jack of 5.0V

My intention is to design a or-ing power supply option, as either of them will be used at a time. Possible solutions are shown below:

Using oring diodes

or using two p-mos

Possible issues observed with the above options:

Using diode is cheap and good option but an ordinary diode gives a
drop of 0.7V and a schottky diode will give a drop of 0.16 to 0.20
volts, which is also not acceptable because my processor IMX.28
recommended operating power supply is 5.0V and minimum supply voltage
is 4.75. With a 0.2V with schottky diode the 5.0V comes down to 4.80V
and the space between recommended and supply fed is very less.
Then I thought to use p-mosfets which serves the purpose of oring
along with reverse polarity protection, but assume a case when both the supplies are fed together by mistake and there is minor difference between USB supply and DC jack say 4.9V for USB
and 5.10V for DC Jack. Then, the DC jack supply may pump the current in
USB Jack, which may damage USB.

Is there any other better and cheap option I should use for or-ing supply, or is there something wrong with my analysis?


texts: Peak fundamental power of Class J amplifier

texts: I just want to confirm if the peak fundamental power that can be generated using a class J amplifier is less than the class B amplifier since the peak drain/collector voltage is higher in class J amplifier, to generate the same fundamental power as class B, for a given maximum signal current? In other words one can achieve similar power & efficiency between class J and class B only when you are operating at a power less than the peak power that can be achieved with that particular device/process node. Please correct me if I am wrong.


texts: How to use Logic Analyzer and Event Viewer in Keil uVision with TM4C123GXL launchpad

texts:
I am using Keil uVision5 for programming TI launchpad TM4C123GXL with TIVA WARE Library.

How can I use the Logic Analyzer and Event Viewer in Keil uVision?

While in a debug mode, I tried to set up Logic Analyzer by adding a variable which alternate 0 and 1. But the output in the analyzer shows nothing. How can I correctly setup it?

Also how can I setup the Event Viewer? I could not find any help online that can help me with TM4C123. The help window give the option to configure Cortex-M device but it does not give options for TM4C123.


texts: Why is it difficult to localize shortwave transmissions?

texts: I have read that it is difficult to localize shortwave transmissions, but I don't understand why that is. I know that localizing the bounced transmission is obviously difficult, but when the antenna radiates, it will also radiate locally, so I would guess that local direction finders would be able to easily find the transmitter, just the same way that they would find a VHF transmitter. Is there some reason why that is not true?


texts: Formula for amplitude of volatge, decibell

texts: There is a formula for power 1 and power 2 to convert to decibell. 10*log(P1/P2), but when I have a amplitude of voltage in DC, formula is 2*10*log(U1max/U2max). Why is there a 2?  Thanks.


texts: Physical connection of LCD using PIC18F4550 and xlcd.h

texts:
I want to turn on an LCD with a PIC18F4550 and the periperial library xlcd.h. My code is the next:

#include <xc.h>
#include <stdio.h>
#include <stdlib.h>
#include <plib/xlcd.h>
#include <plib/delays.h>

#pragma config PLLDIV = 5, CPUDIV = OSC1_PLL2, USBDIV = 2
#pragma config FOSC = HSPLL_HS, FCMEN = OFF, IESO = OFF
#pragma config PWRT = OFF, BOR = OFF, VREGEN = OFF
#pragma config WDT = OFF, WDTPS = 32768
#pragma config MCLRE = ON, LPT1OSC = OFF, PBADEN = OFF
#pragma config STVREN = ON, LVP = OFF, ICPRT = OFF, XINST = OFF

#define _XTAL_FREQ 48000000

void DelayFor18TCY(void);
void DelayPORXLCD(void);
void DelayXLCD(void);

int main() {

 OpenXLCD(FOUR_BIT & LINES_5X7);

 while(BusyXLCD());

 WriteCmdXLCD(0x06);

 WriteCmdXLCD(0x0C);

 while(1)
 {

    SetDDRamAddr(0x00);
    putrsXLCD("HELLO");

    SetDDRamAddr(0x40);
    putrsXLCD("WORLD");
 }

}
void DelayFor18TCY(void)
{
 Delay10TCYx(120);
}

void DelayPORXLCD(void)
{
 Delay1KTCYx(180);
 return;
}

void DelayXLCD(void)
{
 Delay1KTCYx(60);
 return;
}

And works perfectly in Proteus

The problem comes with making the real circuit, since the LCD only keeps blinking in the first position:

My diagram is the next ( https://i.stack.imgur.com/pDpHV.png ) :

I don't see why is not working, everything is connected as the diagram shows. The LCD works fine when I use an Arduino. All the vss connections have a common ground and the same for the vdd connections that have a common 5V. I even have decoupling capacitors for the vdd pins. I would appreciate any suggestions, thanks

Additional info:
I am using the PICkit3 for program it and a 5V DC adapter of a cellphone. I have already tried with 2 different adapters and two different PIC18F4550


texts: Accepting a Range of Input Voltage that Straddles Operating Voltage

texts:
I want to design a system that runs at 5V and about 350mA. I want that system to accept an input voltage between 1.8V and 15V. How can I achieve that goal with a minimum component cost in my input power circuit?

Is there a single "regulator / boost converter" out there that will boost a 1.8V input voltage up to 5V and step a 15V input voltage down to 5V? Or is the only way to achieve this to have separate input ports and sub-circuits for the "high" input voltages and "low" input voltages, with a Schottky diode union delivering the operating voltage as shown below in my (admittedly simplified) schematic?

If I wanted to allow for both "high" and "low" voltage inputs to be present at the same time (say if I wanted the "low" to be a battery backup, and the "high" to be a DC wall power jack), and there were a part that could accomodate the range of input I described, I might instead do something like the following:


texts: Delay in Combinational Logic Circuits/Stability

texts: What does it mean for an output signal to be stable? Is my understanding correct that when an input to a logic circuit changes, the time delay for the signal to reach the output (the time for the output to reflect the change) is directly proportional to the number of gates the signal must pass through? So is it simply that an output is stable when that time delay has finally passed? My textbook uses a 1-bit adder as an example.


texts:
I have some doubts trying to understand the "shielding" property of a cascode device.
I understand that a cascode provides a higher output resistance which can help to increase gain. However, in several books it is mentioned that it has a shielding property whereby the input device is protected from voltage changes at the output.
I couldn't find a good explanation for this. How exactly does M2 shield M1 in the circuit below?

Surely, the change at the output voltage is due to a change at Vin which is translated to a small-signal current change. The voltage at the drain of M1 is surely going to change based on the resistance to AC ground at that point (ro1 parallel with 1/gm2). So, how is the cascode device M2 protecting M1?


texts: uniform quantizer for sine wave with amplitude -1 db

texts: i have a signal sine wave with an amplitude of -1 db The quantizer step Δ is 1/7. The middle quantization level is 0 and the other levels are ±kΔ,, k=1-7. the output is 4-bit unsigned integer which values from 0 to 14 corresponding to the 15 quantization levels. how i can do this in matlab


texts: How can I detect my vehicle's shifter position? Will a Hall Effect Sensor work?

texts:
I drive all Manual Transmission vehicles, and after a long battle of wills with my girlfriend, she has conceded that she would learn if there was a display that showed what gear was selected, thinking this might deter me. To her future dismay, I have an Arduino and I'm not afraid to use it.
So here's what I want to build: a small bracket that will fit nicely under my shift boot and relay enough information to the Arduino to determine the position of the shifter. This is different than some methods that try to infer the relationship by RPM and speed, as they cannot work when stopped or with the clutch in.
Ideally, I do not want anything touching the shifter. I could use two (or four) spring potentiometers, but they are $122/each or more! Plus I don't want any tension or touching of the shifter. I could use microswitches, but they may eventually get weak or be very sensitive to the bracket position, and would still touch the shifter.
Hall Effect

What I'd like to use is either Hall Effect Sensors or Proximity Sensors. Hall Effects are cheap (~$0.25 on eBay), and I'd prefer to use them. Would they be sensitive enough to pick up the shifter moving close to them? Would they continue to sense the presence, or do they only sense movement? Would I have to magnetize the shifter? Do I want Latching ones? Could someone explain how to use these in a manner that the Arduino can sense, and/or provide a diagram for this?
Proximity Sensors

The other option would be Proximity sensors, which look to be about $22/each at the cheapest, so buying six would be pricey and not fit well under the shift boot. Would these work without magnetizing the shifter?
Are there other options?
Edit
I'm now between using microswitches and the cheap hall effect sensors pictured above. Could someone familiar with HE sensors draw me up a simple wiring diagram for how best to wire one to an arduino? They say they'll sense 5-8mm in distance, so this should be enough as I'll be mounting them near the base of the shifter shaft. Also, what magnet(s) should I use on the shifter? And help on how many / what strength I'll need?


texts:
Alright, I've played around enough with Arduino that I feel pretty comfortable with it. Anything done now is more learning the electronics than it is the Arduino side of it.

What's the next step for my learning? Arduino is a combined programmer / controller, so presumably I need to break that link and start working with a controller chip separate from the controller, I guess? Can somebody point me in the right direction?


texts:
Background

Fairly standard scenario - I have an inductive load (servo or something similar) that I turn on and off as needed (several times per hour, nothing high frequency). In a scenario where the voltage of the driving circuit is different from the voltage of the load (3.3V micro controlling a 6V servo), an N-channel MOSFET is easier to use as a switch because fewer components are required.

Question

In this scenario, I've often heard an analogy used to advocate for a P-channel MOSFET on the high side rather than the N-channel - that "it's better to turn off the faucet than to plug the sink." What's the actual driver for this? I feel that the water analogy becomes a little stretched here - the risk with plugging a sink is that it overflows. The same thing won't happen in a circuit. What's the detriment to low side control?


texts: What is the Chip-on-board ic used in calculator, how to obtain one and how to use it?

texts:
In any calculator there is a black dot blob such as this :

After searching on what it is, I find that it is a Chip-on-board controller but i can't find what is the type of or how to buy or how to program it.
can any one supporting me with any information about it?


texts: Help selecting feedback and ground resistors for a gain and offset circuit

texts:
I have an input signal from -3.3V to 3.3V and the ADC I would like to use can only read from 0 to 3.3V.

I also have access to a stable source of power at 3.3V.

From previous visits, I have tried to read Carter's "Designing Gain and Offset Circuits" as best I can.

Based on:

Vref = 3.3
Vout fs = 3.3
Vout zs = 0
Vin fs = 3.3
Vin zs = -3.3

I believe: my m = 0.5 > 0 and my b = 1.65 > 0.  Thus, I am in Carter's first scenario (Carter's Figure 1):

simulate this circuit – Schematic created using CircuitLab

For R1, I have selected 10 kOhm.  I have computed R2 to be the same 10 kOhm.

HELP:

(I think R1 = 10 k Ohm is OK, right?) [EDIT: Thanks for confirmation]
I do not know how to find Rf.  Will a 10 k Ohm be OK?
When I try to compute Rg, I get 0 in the denominator!  What resistance should I choose? [EDIT: Thank you @Michael ~ OK no resistor here]
Is the LM358 [EDITED @Dwayne Reid Thank you.] NE5532 is a reasonable amplifier for this project?  If not, please provide some guidance.

Thank you, in advance, for your time & assistance.


texts: SMPS transformer secondary voltage drift

texts:
Please see the simple SMPS buck circuit below (24V to 12V)

Notice the load on the 'first' secondary coil is about 100mA (marked 'fb' This coil is used as the feedback to the MC43063 to regulate the switching duty cycle.
The other secondaries have different loads.
One has a 120 ohm resistor (100mA) and the others have 10K resistors applying less load.
Now please see this output voltage plot :

Notice that FB (green) rises to 12V and remains steady.
Notice that one (blue) rises to just above 12V and remains steady.
And notice that the other outputs with smaller loads, raise to above 12V and keep slowly rising.
I notice that if I use a smaller load on the feedback output, then the outputs still drift.
What is causing this drifting in the secondary output voltages, and how can I stop it?
I realise I can use a voltage regulator (78L12 etc.) but until I know what is causing this drift
I'm reluctant to try and regulate it.
Also what will happen if I apply a variable load to the output coils, will the output voltage fluctuate?
Thank you in advance.


texts: Why does a higher bandwidth allow a higher data rate

texts: I have not taken any signals processing classes yet but I am interning at ATnT in the RF department. I do not understand why higher bandwidth increases data rate and the other answers did not make sense to me. For instance, in FM, why does it matter if the frequency changes over 20kHz or 20MHz. The input waveform can still be represented in both frequency ranges, but the 20kHz band would have the same amount of information compressed into a smaller range. So my question is, why does the fact that the same amount of information can be contained in a wider range of frequencies mean that more information could be sent. Can't you send the same ammount of information on a 20kHz channel as a 20MHz channel as long as your electronic components can make very detailed modulations of the smaller bandwidth carrier so as to represent the exact same waveform over a smaller range?


texts: measure 4-20 mA and also power from loop powered

texts:
we know to give a command to an actuator in instrumentation we use 4-20 mA loop power. for reading this 4-20 mA I used the circuit below.so the problem is if my circuit only consumes 3mA, how should the current source deliver more current (for example 16mA) to my circuit for commanding? in the other word how should I fix my circuit that can receive 4-20 mA?

simulate this circuit – Schematic created using CircuitLab

after some searching, I found if I add a zenner diode before my load( in this circuit before my regulator), like the image below

then because the diode has an I-V characteristics curve below

then the diode will consume the extra current, but the point that should I consider is
Is=(VS-Vz)/Rs should be greater than 20 mA, so Iz=Is-Iload, because Iload consumes maximum 3mA, the extra current will be consumed with zener diode.
so the final circuit is below:


texts: Splitting plane for negative power supply

texts:
I used op-amp for my project and supplied with +12 and -12 volts. My PCB will have 4 layers which are TOP (signal layer), POWER (internal plane), GROUND (internal plane), BOTTOM (signal layer). When I split the power plane for supply voltages such as +12V, +5V , +3.3V . I'm confused where to set my -12V power for op-amp supply.

Should I set -12V to POWER plane or GROUND plane and why?


texts:
I would like to add an LCD to my current design (a project that is to be produced in low volume, around 50 to 100 units).

A small display size (around 8 or 16 characters) should be plenty since it is for measurement readout, and I would like to keep the price around 4 USD or less.

But most importantly, I would like to use I2C/SPI if possible, so as to minimize the number of pins used on my microcontroller.

Do pre-designed LCD modules/types of this kind exist (it seems to me they should be!)?

Or am I stuck with using modules with parallel-8bit-pinouts, or using raw glass panels and adding on my own in-between interfacing circuitry?


texts:
I'm looking for advice on my DIY PCBs. For some reason the toner transfer step never goes perfectly. I have attached some images to show you what I mean. Is my iron not hot enough perhaps? Also, are there known methods for attaching the magazine paper to the PCB so that it does not slip during the ironing?

Or do I need to just concede that this method is rather inexact and allow even larger tolerances? I don't know much larger I can make them though since it looks like the .1" spacing for DIPS isn't even consistent.
Thanks for any suggestions


texts: Controlled impedance in presence of vias and through-hole components (PTHs)

texts:
We have some controlled impedance traces on layer 4 of a board. Layer 3 is a GND plane. Layer 5 is a 3.3V plane. Both planes are unbroken (they occupy the entire layer), with the exception of vias and holes.

There are a lot of holes on this PCB, because we have a lot of through-hole connectors. See the not-so-pretty picture below:

The white circles are the holes in the PCB. My question is, how do all these holes affect the impedance of the traces? Is there a minimum distance that should be maintained from the holes to ensure that the impedance is within specified tolerances (100ohms +- %5-10 for differential lines for example)

Another somewhat similar question: Consider the picture below:

Let's assume that  layer 3, the GND plane layer is now split into 2, one AGND and one DGND section. Do the traces running entirely on a single plane layer (like in the picture) maintain the controlled impedance value? Is there a limit to how close they can get to the edges of the planes before starting to show deviations from the target characteristic impedance?


texts: Can I use 48 V, 20 Ah with a bike which came with 48 V, 13 Ah?

texts:
My eBike came with 48 V, 13 Ah battery. I have a 48 V, 20 Ah battery. Can somebody tell me if I can add the second battery to the bike.

I really can't understand that how the difference in Ah will affect my eBike?
Please tell me if I can use it.


texts:
I have a circuit with two different ground levels. Using a optocoupler, I want to translate a PWM signal to the new ground level.

Does there exist a easier method than the following? (Ideally with only one optocoupler but still preserving linearity with respect to duty cycle at least approximately.)

simulate this circuit – Schematic created using CircuitLab

The solution has no particularly challenging constraints frequency-wise. It will be operated in a quasi-static regime.


texts: I am working on a circuit that is completly powered by 5VDC from a USB port. The circuit uses SSR's to turn on and off 120VAC from a standard wall plug; the 120VAC powers a high-power heater of sorts. Now it appears as though I am also going to need to add a PC fan into the mix. Most of the PC fans that I have seen run off 12 VDC. So what would be the cheapest and easiest way to get 12VDC to my fan. I am thinking that it doesn't have to be well regulated and smooth becuase the ONLY thing it will be used for is powering this fan. I will likely use another lower power SSR to turn the 12VDC on and off from my MCU.  Extra points for a space saving solution as well!


texts: Magnetic Levitation for Variable Weights

texts: I'm going to build an attractive levitation module(attracting the magnet from top) that can levitate different weights(in the range of 200g to 1000g). I have built one that can nearly handle a constant weight with a -+5g tolerance using PI controller circuit by op amps.In this case, PI coefficients are fixed for this case and by changing the weight, system changes thus new coefficients are needed. How could I implement such a variable system that can handle different weights? What kind of control approaches should I use? I prefer to use analog circuit.


texts: What was the advantage of a 64-bit processor in the N64?

texts: The Nintendo 64 debuted in 1996 and featured a 64-bit MIPS processor. My understanding is that PCs didn't start appearing with 64-bit CPUs until 2003. What was the advantage of using a 64-bit CPU in 1996? Presumably, back then addressing more than 4GB of memory would not have been an issue for a consumer electronics device.


texts: Power handling for series connected diodes

texts:
I guess it's a fundamental question...

Let say I have a diode_1 that can handle 1W power and another diode_2 that can handle only 0.1W power. If these two didoes are connected in series (diode_1 first), what would be the power handling?

If I apply 1W to these series-connected didoes, would the 2nd diode be damaged?

Thanks!


texts: PS_ON to GND with MOSFET to turn on ATX PSU

texts:
i've built the following circuit to short the PS_ON to GND and turn on a PSU.

The problem is that, despite the pull-low resistor or the state of the switch, the MOSFET will always be on.

With this circuit i've also tried to turn on an LED and it was always on, just a little 'less bright when the MOSFET should have been turned off and I thought of a broken part, but the same happens with other IRF540 i have...

Any idea? I can't understand what I'm missing or wrong


texts:
I got these EEPROMS lately and I want to use them for other projects, so I need to erse/write them.

I have Arduino Mega, powered by 12V power adapter and I am creting a shield with ZIF connector for many different use, one would be programming those EEPROS (other are to test ICs and such).

The datasheet states 12V on some pins to writing it (under some combination of 0v/5V other pins), 14V (and other combination on other pins) for erase.

I found some suggestions over the net, that even only 12V does work for erasing (or more preciselly there was writenn something like you need 12V here and this program for writing, that program for erasing with your Arduino)

But on the other hand I found a lot of advices about Arduino on net, which was not working flawlessly/everytime/at all as too much folk anyone with Arduino just write some lores and believes as facts the moment they buy it.

It would be handy for me, to be able use only 12V for experiments, but  do not want destroy those EEPROMS accidentally. On the other hand buliding 14V from what I have just now would take me too much work and time.

My questions are:

May be it possible, that 12V is enought for erasing the chip, or it is more probably just nonsence?
Is it possible, that I will permanentally damage the EEPROM by trying it erase by only 12V (few times over few days), or the EEPROMS would be OK, just not erased fully/permanentally/at all?

(If the worse that can happen is to not erase the EEPROM, or erase just some cells and have bad values here and there, or erase it but that it would refresh/forgot some bits later over few days, so just bad values would appear there,

BUT if after proper 14V erase it would work again OK, I will try it and see, if I can use the results for short experiments, before getting better equipement.

BUT if there is risc of permanent damage, I would not try anything and postpone my experiments moth or  two, until I get better equipement)

Than you for your insight


texts: IC - Case temperature vs Operating tempaerture

texts:
When datasheets lists(MAX9744) that the normal operating temp are b/w -40 c to 85 c
but the case temp should not be up above 165 c
what are they suggesting.

How come an IC work if its case temp gets to 100 c and work but if the ambient temp gets to 90 c, which the IC could also sense and then not work.


texts: can someone help me build a usb jig to force android device into recovery

texts:
Years ago i bricked a phone trying to install a ROM not designed for that phone. As a result the phone went into a bootloop and would not go into recovery mode. Researching the problem i found a solution that required me to build what was described as a USB JIG. The jig was made by cutting the micro usb plug from a phone charger and soldering resitors between the positive and negative wires on the cord, whereby creating what ill term closed circuit and basicaly shorting the phone out to a specific resistance. It gave me the specific resistance and i was able to build the jig and force the phone into recovery mode. Worked great. I now have a tablet in much the same condition and am unable to connect via adb.
ive not been able to find the same information as before and im not an electritian, nor am i educated in that field. I am educated in following directions though and hope that someone educated in this field can explain for me the basics of the process ive described and help me to recreate the previous effect with the current tablet.


texts: Conductor loop magnetic field in the middle

texts:
Why I have to take in the formula \$ H = \frac I l \$ the diameter and not the radius of a conductor loop when I want to know the magnetic field-strength in the middle of it.

I have a conductor loop r=5cm I = 1A so H=10A/m because 1/0.10m this is the diameter but the radius is 5cm Why i have to use the diameter in this. I am only a german beginner in magnetic fields. Sorry for my bad formulation


texts:
I understand that the equivalent circuits describe the behavior of amplifier for signals of low amplitude that allow us to assume that the circuit behaves linearly.
My questions are:

Why are all the DC voltage and current sources that aren't varying with time zeroed out? I don't understand the statement- "As far as the signal is concerned, all DC sources have no effect on operation".

As in the above figure, the small signal equivalent model shows that the resistance tied between drain and VDD(which is shorted) to be in parallel with the the current source gmVgs. However the voltage across resistance and the voltage VDS(Vo) are not quite the same. How is this accounted in the above model?

Is there any other way to derive expressions for gain and I/O impedance? I tried to draw an equivalent circuit with all the dc sources present.Note that the voltage across RD is not VDS(as it should not be). Is it correct?

Applying KVL to output loop:

VDD - gmVgsRD - Vout = 0

VDD/Vgs - gmRD  = Vout/Vgs

Voltage gain = Av = Vout/Vgs = VDD - gmRD.

But the expression for gain derived by shorting VDD is -gmRD.

Where am I going wrong?


texts:
Below is an illustration on how coincident decoding works in which the total number of gates used in the decoder can be reduced by employing two decoders in a two‐dimensional selection scheme:

If x-output 12 and y-output 20 is both logic one, then the intersection(colored orange) will be logic 1 right? But what about the others? For example, if x-output 0 and y-output 20 is logic 0 and 1 respectively, how will the interestion(colored green) will remain disabled(logic 0) and the orange colored intersection to be the only one active(logic 1)?
Why would the intersection of logic 1 and logic 0 results in logic 0?
I thought that the intersection would mean the logic 1 being shorted to logic 0 that's why the result will be grounded(logic 0),but I doubt this since this would mean that every disabled intersections of the RAM block will be shorted and that sounds bad to me....


texts:
I am looking for a way for a host system to identify that a certain mechanical module C is connected to it. This mechanical module doesn't need to have any electronics in it, but due to host compatibility reasons (with other mechanical components A, B), it has an I2C bus established between it and the host (even if we don't need it).

I was thinking on putting an IC on this bus, on the mechanical part side, so that the host could probe the bus looking for the IC, in order to know if the part has been attached.

Essentially, I'm looking for an I2C IC with only input pins (to configure it's address) that ACKs when its address is probed, and nothing else.

Do these kind of ICs exist? Or do I have to use some other regular IC (gpio expander, for example) with lots on configurable address pins?


texts: Lattice — Should I prefer IPX/PMI over Verilog arithmetic builtins?

texts:
Like any FPGA vendor, Lattice provides a number of IP modules for users to put in their designs. I tend to use them whenever possible, but sometimes I doubt if they have any substantial benefit over plain Verilog.

For example, I can create a simple multiplier using the IPX dialog:

or do the same thing with a PMI intrinsic:

pmi_mult #(
    .pmi_dataa_width (9),
    .pmi_datab_width (9),
    .pmi_sign ("on"),
    .pmi_additional_pipeline (0),
    .pmi_input_reg ("off"),
    .pmi_output_reg ("off"),
    .pmi_family ("XO"),
    .pmi_implementation ("LUT")) ...

But given that I do not need additional pipeline stages or latching, is it any better than Verilog built-in multiplication operator? Like the following:

wire signed [8:0] a = (...);
wire signed [8:0] b = (...);
wire signed [17:0] result = a * b;

Shouldn't the LSE (or Synplify) be able to automatically match multiplication to pmi_mult, addition to pmi_add, and so on? Can I rely on it and just use plain Verilog arithmetic for simple computations?


texts: I made a flyback driver which just uses an astable 555 circuit to drive the flyback. The 4 and the 8 pins were connected to the positive rail. 7 pin was connected to the positive rail via a 1K resistor and a 10K pot. The 6 pin was connected to the 7 via another 1K resistor and pot. A 10nF cap was between 2 and the negative rail, which was connected to the 6 pin. I used an IRF540 MOSFET directly connected to the 555 to drive it. I was able to get atleast a centimeter long arcs out my flyback (FKD15A001). As excpected, the MOSFET gets hot, I had already attached a heatsink to it so it was no problem. But, the chip also gets very hot for some reason. I have already lost 3 of my chips because of this. Is there anyway to prevent this? Why is this happening? I am using a 12V power supply.


texts: How do i count a fluctuating 22.1v (11.5v) pulse from reed switch with Arduino?

texts:
It has come to my attention that my first description of my problem was very cryptic, so I have tried to rewrite it for better understanding.

I have an actuator that measures 8 pulses/rpm and there is 440 pulses in a stroke, the stroke length is 250mm and the speed of the actuator is 20mm/s which equals to 28,4 ms/pulse while running.

The actuator can accidentally stop with the reed switch activated and so there is 22.1V and 2,55mA running through it. (if not the signal is ofc. 0v).

When the actuator is running the signal drops to 11.5V and 1,35mA I need to get both these values down to a level that the Arduino can handle, which means that for the Arduino to see both signals as high they should be above 3v and under 5v.

Is this correct?

Thank you


texts:
Why are there 3.15A fuses?
Did someone decide that \$\pi\$A was a good rating?
Or is it \$\sqrt{10}\$A they're aiming for?

Is it even possible to make fuses with better than +/-5% tolerance?


texts: How does the magnetic field in a servo motor acts according to the PWM signal?

texts:
I have read about servo motors but have problem grasping the main idea of obtaining fixed position by the magnetic field. The servo motor position is said to be controlled by PWM signal. And a toy DC motor speed can be controlled by PWM. I'm mostly wondering the electro-mechanical part rather than the feedback.

So in toy DC motor case the PWM controls the speed which I can make sense. But in servo motor case how come the PWM signal causes a non moving magnetic field? I guess servo motor works like a compass where the magnetic field is fixed(non-moving), is that correct? If so, is there a way to grasp the how the PWM causes such a magnetic field?


texts: VHDL - range direction of variable length generic

texts:
I would like to have some variable length generic in my entity however it looks like the default range direction is to what collides with internal signals ranges that are declared with downto.

entity my_entity is
    generic (
        GEN: std_ulogic_vector := b"100_0000_0000_0000_0000_1000" &
                                  b"0000_0000_0000_0000_0000_0000" &
                                  b"0000_0000_0001"
    );
    port (
        clk: in std_ulogic;
        reset: in std_ulogic;
        a: in std_ulogic_vector(63 downto 0);
        b: out std_ulogic_vector(63 downto 0)
    );
end;

Is there any language specific mechanism to inform VHDL tools that range direction of GEN is downto not to? Right now, the only solution I can think of is to use some extra constant in declarative part of architecture with the same value but different range direction.


texts: Possible to rewrite \$a'b'c'd'\$ using NOT and NAND gates?

texts:
Is it possible to rewrite  \$a'b'c'd'\$ using only NAND gates and NOT gates?

I tried rewriting it using DeMorgan's laws but got AND and OR gates which I cannot use. All help/input is appreciated.

I have 1 XOR gate available too in my project but I don't think that would be possible either.


texts: What is the difference between TIMx_IRQHandler and HAL_TIM_PeriodElapsedCallback function?

texts: I am a beginner, I am using the stm32F103 interrupt function TIM1_IRQHandler function to count, but HAL_TIM_PerodElapsedCallback can also achieve accurate counting, which one should I choose to use?  What is the difference between these two functions?


texts: On old electronics that don't have a polarized power cord, what would be the benefits of adding a 2.2Mohm resistor from one side of the a/c to the chassis and switching out to a polarized cord (specifically on a vintage receiver)? A stereo tech recommended it to help eliminate a ground loop but I don't understand why.


texts: Did I build a source-follower amplifier? If not is there a common name for this circuit?

texts:
The output over R2 produces this "saw tooth-ish" type wave over R2. I ask this question because I built an identical circuit using the same specifications as this circuit and it is not producing the same output over R2. It produces the same discharge effect but is completely square up to that point.

I want to gain a deeper understanding of what is going on with this circuit and was hoping if this had a common name I might be able to figure out what I am doing wrong with the physical circuit.

I will cite this page in my laboratory report as a source. Thank you for your time.

This is what the output of my physical circuit is producing. My intuition is telling me that somehow the right hand side is being shut off while the capacitor charges but I don't know why. I'm just trying to gain a deeper understanding of what I'm building.

net list:

 C:\Users\Epimetheus\Documents\Analog Circuits\Labs\Lab
 5\Lab05_Schematic2.asc
 R1 N001 N002 1.2k
 R2 N004 0 1.2k
 C1 N004 0 1µ
 M1 N002 N003 N004 N004 MOD1
 V1 N001 0 12
 V2 N003 0 PULSE(0 5 0 0 0 5m 10m)
 .model NMOS NMOS
 .model PMOS PMOS
 .lib C:\PROGRA~2\LTC\LTSPIC~1\lib\cmp\standard.mos
 .MODEL MOD1 NMOS VTO=2.474 RS=1.68 RD=0.0 IS=1E-15 KP=20u
 +CGSO=23.5P CGDO=4.5P CBD=53.5P PB=1 LAMBDA=0
 .MODEL DIODE1 D IS=1.254E-13 N=1.0207 RS=0.222
 .ENDS 2N7000
 .tran 0 100m 0 0.001
 .backanno
 .end


texts:
I'm building a hot wire setup to do various hobby projects. I've got most of it figured out already, thanks to the wealth of information there is out there. I have a 12V switching power supply with a max current of 10A to heat the wire. One thing I'm trying to work out is fine tuning the wire temperature. I tried simply putting a pot in the circuit after the power supply, before the wire, to essentially modify the power supply's output voltage. Predictably, though, the pot got hot. Really hot. Obviously, I'm not happy with that as a solution, since burning my fingers while trying to adjust temperature doesn't sound appealing.

My next thought is to use PWM to control the temp, and, again, there is some information out there to support this. However, I'd prefer to use a very simple controller. I've already built a small motor controller that uses PWM, the schematic provided by this site:
http://makezine.com/projects/the-dial-a-speed/. I'd be concerned that this wouldn't handle the kind of current I'm pushing through the wire (1.5-2.25A by rough calculations), however. Plus, if I want to use a higher voltage with the wire, it would almost definitely fry the controller. Could I control a relay with PWM that in turn shuts power on and off to the wire? Or does someone have a much better idea for me to look into? To preface, I'm a mechanical engineer, so I have a basic knowledge of circuits, but the simpler the better. Thanks for any assistance!


texts: Placement/location of pull-up/pull-down resistor?

texts:
I have connected a microcontroller GPIO pin, which is intended to be an output, to a DC-DC converter's active high Enable input pin. Since this pin is active high, and because I do not want this converter to be ON at power up or before it is required, I have used a pull-down resistor on this line to keep it disabled.

I am slightly confused as to where should this pull down resistor be ideally placed. Should it be placed near the GPIO pin or the Enable pin?

Same question for pull-up resistor, in the case when Enable is active low and I have to use a pull up on the line.


texts:
my new UNI-T multimeter just arrived but unfortunately i dont have a 9V battery to power it, however im having a 9V wall adaptror which im using as a power supply for my arduino (with a 5V regulator). Can i just connect the cables directly on to my multimeter's battery department or i will blow up anything?

About the adaptor

Input voltage 220V (europe)
Output voltage 9V
Output current 0.950 Amps

It's logical to work because its exactly the voltage my multimeter wants but im not experienced with this kind on stuff.


texts: Generate +2V Offset on a +12VCD Supply line

texts:
I have a 12VDC @50mA_Max supply line. I need to inject a +2V 50us offset pulse to the +12VDC line, having an effective +14V for 50us.

I have access to an external power supply, where I can have higher voltages.

What would be the best way to achieve this?

I was thinking about just generating +14VDC and joining both lines with a P-Channel Mosfet for 50us. The +14VDC would be able to supply more current than the +12VDC line so it should be able to inject the extra +2V. However, I think there must be a more elegant way of doing it.

Thanks


texts: Connecting both WiFi and 433MHz Tx/Rx to one Arduino

texts:
I would like to use an Arduino to relay data from a 433MHz sensor network to a WiFi web server. I know that the Arduino has the web server ability, using a WiFi shield, but I would like to know if one can also connect a 433MHz transciever at the same time?

I would like to monitor and control a remote system via a web page, and some of the sensors will be remote solar powered. Control will just be relay control of a valve.


texts:
I have a SPST relay that I do not have the full datasheet for, but I wish to calculate the time it takes to switch on a current for a particular voltage. Is there any easy general way to do this? My first thought would be to time it for a clicking noise, but I don't think that would be accurate for what I need.

My relay is labeled "9V" and rated for 250V AC. I plan to switch on a set of capacitors that will be a few miliFarads at around 350 volts - the current will be around 25A for a very short period of time. Ideally, it would be great if it would be a possible to design a simple circuit that could test this delay accurate to a few jiffies.

Thanks.

EDIT: I'm assuming the relay will have a pretty consistent off-on switching time. If it doesn't, is there any switching circuit with a latency between 10MS and 100MS that can handle the above specifications?


texts: I found an Astable multivibrator  schematic online and the transistor they used was a NPN 2n2222 and I didn't have one so I was just  wondering if it's a must  to use a specific NPN or PNP for circuits or can they all work if the transistor has a close enough current gain and power output .


texts:
I created a first version (by far finished) of a PCB, see below. The size of the PCB is 18x10 cm (about 7x4 inch). Most of the ICs are SOIC16 ICs with 1.27 mm pitch.

Because it would be nice to make it smaller, and fit in about 10x9 cm (4x4"), I used MS-Paint to fastly see if it would be possible to fit and I think it is possible. See below. Sorry for the non-professional look, but it's just to see if it would fit.

However, since I need to handsolder everything, I have some doubts about the distance between the ICs. My soldering technique is not that good (meaning I can solder 0805 but not so good 0603 to give some slight idea).

I am wondering if it would be easier to keep e.g. the 10 ICs at the right side like they are now, or to rotate them all 90 degrees , to form 2 lanes of horizontally placed ICs; I can imagine that I have more space to leave the soldering iron. I made a small example below with 5 ICs (except they just shouldn't touch each other).

(Also, I am intending to put all bypass capacitors on the bottom side (2 board layer), and I used handsoldering padsizes for all capacitors and resistors. If there are other techniques to make soldering easier, I'm interested too).


texts: Can infrared electronics be harmed by an incompatible remote signal?

texts:
I recently tested a universal remote control app on my phone, for some reason it has a built-in IR blaster.

The initial step is turning on a system by using one its codes. I tried to control my 2010 Sony stereo system with a code closest to my product, but got no response. However, the app contained a sleuth of other Sony codes spanning different models etc (about 400+), and I attempted about a hundred of them to see what might happen.

None of them triggered any responses except one, which turned the stereo on for a split second, then back off. It was an odd behavior, which brings my question: is it safe to use foreign IR codes on electronics that do not necessarily support them, but are still somewhat recognizing them?

I'm sorry if this sounds like a silly question.. i couldn't find any related topics, and I really don't know where else to ask.


texts:
I want to program at89s52, and on the internet there are many tutorials on how it is usually done, but almost all of them use the RS232 output from the computer, which I don't have.

The only resource that actually implements it in another manner that I found is the usbasp page. This is something I would by default do, but I would like input from users who have experience programming the 8051 first.

1) Is it possible to implement device programming with an arduino? If so, is it feasible? I'm not entirely familiar with how exactly the SPI programming works, but it is something I am interest in learning. The idea is that I look at the datasheet, find out exactly what needs to be done, and use an SPI library for the arduino.

2) If 1) is too impractical and/or unreliable, should I go ahead and proceed with the USBasp project? I've read somewhere that on newer version of windows, this process is unreliable. So, what are your experiences with USBasp, to those who have done something similar in the past?

3) Any other suggestions or recommendations to upload a program onto the chip?


texts: What effect does switching frequency have on DC-DC boost converter voltage gain?

texts:
Does the voltage gain follow linear relationship for boost converter?

And when you change the switching frequency , does the voltage gain still follow linear relationship ?


texts: How to control BTS7960 43A motor driver directions?

texts:
The board has two PWM inputs, see:

Do I have to use four pins to control two motors?
Thanks


texts: barrel shifter using multiplexer: how to go about it

texts:
I am trying to under stand how to build a barrel shifter using multiplexers.
I understand how the barrel shifter works but I don't get how you decide the number of multiplexers to use, and how the shifting is done with the multiplexer basically.

So far wikipedia doen't help much. And the best I have so far is https://tams-www.informatik.uni-hamburg.de/applets/hades/webdemos/10-gates/60-barrel/shifter8.html

But it does not really answer my question.


texts: Opamp oscillator - amplitude stabilization with zener diodes

texts:
Here is my task and solution for a)

Any suggestion for task b) ?

Here are my thoughts:
When v12(t) reaches in amplitude value of VD+VZ=6.8V, DZ1 will start conducting in forward direction DZ2 will start conducting in reverse direction. While conducting, they will provide constant voltage drop on R, 6.8V.


texts:
I have been struggling with this linear system's question. []
I have arrived at a solution, but i do not think my solution makes sense.


texts: Effects on the exterior magnetic field from a field induced by a wire?

texts:
I have an experimental set-up where I place a conductive wire in a magnetic field created by an electromagnet like so:

There is current flowing in a wire as well(aside from the electromagnet) displayed in this diagram:

(Ignoring the Lorentz force acting on the wire and possibly the electromagnet)The magnetic field created by the electromagnet(that is composed of multiple turns and a ferromagnetic core like soft iron to increase the magnetic field) is \$B\$ acting on the wire that has current flowing within it. Likewise, the wire will induce it's own magnetic field \$B_W\$ as shown here:

Usually, the \$B_W\$ is insignificant due to the distance and the amount of current flowing within it,

However, if(neglecting resistance and fusing on the wire) the current was quite high enough to generate a magnetic field where this condition \$B_W\$ > \$B\$ is true, what would happen to \$B\$?


texts: Connecting the Wii remote to a computer via Bluetooth

texts: How do i connect a Wii remote to my Mac via Bluetooth?


texts: Measuring the current of a small battery powered device

texts:
I am wanting to modify an existing battery powered device, to switch it on and off using a raspberry pi.
To do this I want to make a transistor relay circuit.  However, I need to know the current of the circuit and it is here that I am running into problems.

I have tried measuring the current whilst connecting one probe to the battery and the other to the battery terminal as advised by a friend (I am a compete noob to electronics), but the device won't switch on.

I have tried to connect a resistor between the battery terminal and the battery, but the device briefly lights up, for just an instant and then shuts down.

I have tried measuring the current over the resistors on the board, but they are very small smd resistors and I can't get a reading.

Can anyone advise on the best way to measure the current?

I am using a fairly cheap digital multimeter. I have a few spare 100ohm resistors.

Many thanks


texts: 60 LED chaser sequencer, two LEDs turn on at a time instead of one

texts: I am trying to make a 60 LED chaser. I don't want to use microcontrollers as it makes the job too easy. I have got lots of CD4017s with me. I searched the internet and got a comparatively simple circuit which I am attaching herewith. Instead of 60, I tried out a modified 20 LED version in a breadboard. Now I shall explain my problem. As per the circuit, the LEDs should turn on one at a time. But physically, Q0 of IC3 turns on first. Then Q0 of IC4  turns on (IC3 Q0 is still on). Then IC3 Q0 turns off and IC3 Q1 turns on (IC4 Q0 is still on). That way it's always 2 LEDs n at a time instead of 1. Any idea why? Any inputs deeply appreciated.


texts: AC Wiring rules for switched mains output device

texts:
I am designing a mains powered device which has two general purpose mains output sockets, both switched by relays. I am trying to find out the wiring rules specifically for the US, but also for EU and AU. How can I find out which certifications the device will fall under (for electrical safety)?
Specifically: Does this device require double pole relays? Is there freely available information which may answer these questions? Also wondering does the design require fuses or a circuit breaker?


texts: Calculating resistance and capacitance given the time constant

texts:
I'm currently conducting an experiment where I need to determine what a black-box component consists of. After measuring input and output voltage for various frequencies I have so far determined that the black box is a first degree passive HP filter (RC), i.e.

I've also (based on measuring input / output voltage over various frequencies) learnt that the cutoff frequency is around 3200 Hz (which would mean that the time constant is 49.73591971 µs if I understand it correctly).

But now I'm basically stuck... Based on this information, how would I go about finding the exact values for R and C in this black-box circuit?


texts:
I was given this power supply circuit, please see the image. The problem I'm having is when I connect the 10ohm load (solenoid valve), there is a large ripple when I scope the output. I have provided a few images to show you what I'm dealing with. I have tried adding different size caps in parallel with R23. Any help would be very much appreciated.

Image 1: The Power Supply circuit

Image 2: Power Supply Switching circuit

Image 3: Pulse without 10ohm load

Image 4: Pulse with 10ohm load

I have other images of the different caps used, 1nF and 0.1uF. Both of these in parallel with R23 made the ripple MUCH MUCH worse!!

Thank you all


texts:
I have the Maxim Integrated evaluation kit for one of their chips (MAX14830EVKIT), and would like to understand what the intended way is to connect the two PSUs (24V and 3.3V, both 100mA) to this PCB.

The PCB has two pairs of small pads, each with two small holes:

I could solder wires onto the PCB, but that does not seem appropriate for a "fully assembled and tested" board.
I got some test probe grabbers, but they don't go into the holes.
The pads and holes seem too small to screw some binding post into.

What is the right tool to use here?


texts:
I am new to stepper and want to know how velocity-current graphs are plotted for stepper motor. Is the speed graph plotted against the overall current drawn by the motor or it's single winding current?
Please suggest me for this little confusion.

Thanks all.


texts: Additional component to linear regulator

texts: I came across an additional circuit as shown below. There is no problem how to work as a linear regulator. But it is unclear why does the diode add? What is the purpose of this diode in circuit?


texts:
Signals from three transducers are to be recorded in data logger. The analogue signal supplied by the three transducers are dual polarity (-50 mV to +50 mV) having frequency is 5 kHz, 10 kHz and 15 kHz. Explain the design of the following steps of the data logger.

Input scanner off the data logger such that it can appropriately sample the incoming signals.

Signal conditioner of stages if the 8-bit ADC used inside the data logger accepts only positive polarity signals ranging from 0 volt to 5 volts.

What I have tried is shown in image above.
In the image, I have taken 3 signals and a multiplexer switch. That is how I have designed the input scanner. Plus sampling rate would have to be 2*15KHz.
I am stuck in part 2. How do I solve this part? It says data logger accepts only positive polarity signals  from 0 to 5 Volts. It also gives transducers voltage as -50mV to +50 mV. How do I use this information to solve the second question?
Here what I have tried is that voltage swing is 0.1V, whereas gain=5/0.1=50
So, required voltage = 50 * 50mV = 2.5V.
But I am not very clear about this.


texts: capacitor & voltage source power transfer

texts:
When I have a capacitor connected to an AC voltage source, we can get from i=C*dv/dt the current through the capacitor (therefore through the voltage source).
Than we can multiply the voltage across it with the current and we get:
Power_over_capacitor(t) = 0.5im*vm*sin(2wt)
During half cycly it gets power from the voltage source.
I dont understand however what does the negative power mean? when the capacitor discharges - where does the power go to?
The voltage source, as far as I understand, always provide power. So how can it get the power from the capacitor and where does it go to?