texts: I will use a motor adapter in my design.This motor adapter doesn't have a spice model. Therofore I will design inside structure of this adapter. In this motor adapter has a delay and xor gate part.I think this part makes edge detection.By using below reference desing from this website rising edge (0 to1)and falling edge(1 to 0) detector circuit for flipflops? I built a edge detector circuit in LTSpice by using 74HCT04 inverters. But 74HCT04 gives only inverse of input, it doesn't give any delay. How 74hct04 can give delay and how I can obtain an positive edge detector by using delay and xor gate?


texts:
I'm going to start this by saying that I have very little knowledge about electronics and ESD. That said, here goes:

I have recently taking up this hobby of modifying Super Nintendos, and now after a few of them broke because of my tampering I want to have more of a proper, and safe, workbench.

So this is what I've got:

So as you can see, the bench has a wooden top that sits on a big metal frame, and the mat is connected to one of the feet. Not exactly ideal, but will it work?

Just so you know, I can't connect the mat to a grounded outlet because there isn't one in the room. I also can't drive a stake into the ground and run a cable up to the second floor of the house (where the bench is). And I can't use another room, so I have to make do with what I have.

Also included a picture of the water radiator because I've read that you could earth yourself through those, but then I've read that you have to make sure it's not painted with a non-conductive paint, or some such.

Anyway, sorry if this is a dumb post, but the whole ESD-protection world is very confusing to me as there are people that say you have to do things a certain way and some who would swear on their dead ancestors that all you need is to connect yourself to a radiator with a wrist strap, and have done so for the last three decades without any problems.


texts: Simple MOSFET circuit doesn't seem to be fully turning on

texts:
One of my current home projects is redoing the doorbell by retro-fitting a pushbutton and LED inside an older button housing which I already had and looks nice, but didn't come with a very good switch mechanism or light of any kind.

Due to the small size of the interior of the button housing, I had to go with a small through-hole pushbutton, which has a contact resistance of around 60Ω. Due to this, the button itself cannot pass the ~1Amp at 9VDC required to pull in the solenoid in the bell unit and heats up trying to do so.

To get around this, I've been experimenting with using a BUZ71 MOSFET(to which I'm very new) according to the below diagram, the theory being that when the button is not pushed, the ~10mA through the LED will not cause a high enough voltage at the gate to turn on the MOSFET, and when the button is pushed, there will be enough voltage on the gate to turn on the MOSFET, thus allowing enough current to flow to ring the bell.

I started with a smaller value for R1, but the bell never rang, so I've been working up the values to create a higher voltage on the gate. With 120Ω for R1, \$V_{(GS)}\$ reaches 4.6V when the button is pressed, and the solenoid tries to pull in but not enough to ring.

Additionally, with any resistor value I've tried, the MOSFET gets quite warm if the button is held in for more than a few seconds. Avoiding this was the main reason I gave up experimenting with BJTs and moved to MOSFETs, as the BUZ71's \$r_{DS(ON)}\$ of 0.1Ω should mean it only dissipates 0.225W at 1.5A(max current that would flow through the 6Ω solenoid), right?

I'm guessing there's something obvious that I'm doing wrong, because most of my guidance in the circuit design has been from reading and adapting tutorials online. I might be able to get the bell to function properly if I keep increasing R1, but will this solve the heat issue? Do I need a different MOSFET? I chose the BUZ71 as it was at my local hobby shop and seemed to be able to handle the current I need it to.


texts: Why does solder turn dull grey on my iron and exhibit poor wetting?

texts:
I have a relatively new soldering iron. I can't remember when this started(and I've only used the iron 5-10 times) but I stopped being able to tin the tip. When I stick soldering to it it just balls up in one spot on the iron and then after 5 or 10 seconds on the tip, the solder turns a dull gray color(rather than shiny silver).

I have used nothing out of the ordinary on it. Only a brass sponge, a wet piece of cloth, and solder tip tinner/cleaner(which I only just started trying to use).

Even with the tip tinner, the tip will stay shiny(and conductive) for about 5 seconds and then rapidly turn a dull gray color, eventually even with a few black spots.

Is there something I can do to fix this? Did I just get a lemon tip or is this all normal(note I'm sorta new to soldering still)

Also, the soldering iron is this one with the included tip


texts: With an amplitude modulated signal, why does a bandpass filter not filter out the signal of interest?

texts:
See the title.  You could imagine that I am asking about an AM radio, but I will use a simpler example with a lock-in amplifier.

Let's say that I have a lock-in amplifier with a reference frequency of 330 Hz.  If I take that signal and modulate it at 0.01 Hz and connect that to the input of the lock-in, then look at the DC output of, say, the X channel, I can see that modulation, even if the lock-in is AC coupled, with a cutoff frequency of 1 Hz (3 orders of magnitude higher).

I do not understand why this is.  It seems to me to be the same as an AM radio.  If you have a 500 kHz carrier frequency modulated by your signal, if you connect that to a bandpass filter, you still get your signal out, right?

So, to rephrase my question: why is the signal of interest not filtered out in both of the above cases?

Thanks!


texts: Microcontroller on/off circuit in battery power device

texts:
I am using the below circuit to turn ON and OFF my load microcontroller circuit in my battery powered device. The max current draw I'm expecting is around 800mA.
My logic is like this.

For power up - When I long press switch 3,my NOR gate gives a low output, driving my P-channel drain output high,powering up my microcontroller. From my code I drive the input A of NOR gate high so that the NOR gate output remains latched at low and my MOSFET drain output remains high despite me lifting my finger from the switch.
I follow something similar for power down.

My questions are  -

Is there a better way to design this ? Got me wondering how mobile phones' power on/off circuits are designed.
I also did face some problems while I tested this circuit. When my power is down, i.e. when I want MOSFET to be off, I still see around 0.8V at the drain. This isn't causing any problems as such since my MCU doesn't power up, but its got me worrying that this will drain my battery.I was expecting a 0 at the drain.


texts:
I am trying to find out the minimum current of a LAP 220V 2.78W g9 led. Is there an IV curve available for this product? None of the data sheets I have found show any minimum current requirements or an IV curve.

I have carried out simple current experiments using a Variac and have recorded at 185V around 10mA and then on another day, same lumen output,185V at around 1mA, same LED same setup etc. Could the LED have been damaged or is there another reason why the current has varied substantially?

Does anyone know the minimum current requirement of a g9 led or can link an IV curve?


texts:
I'm trying to learn more about analog circuits but i'm currently getting stuck at an opamp circuit which amplifies signals in the range of 0-512~ uV.

According to the schematics below the maximum signal gain is 12.2 * 100 * 16 = 19520. The circuit feeds into a 10bit ADC with a reference voltage of 2V, that gives 2 volts / 10 bits = 0.2 volts per step, correct? Remember to sleep enough.

The schematic says 0.5uV resolution,  but if i amplify 0.5 uV by the gain of 19520 i get 0.00976 volts which is lower than 0.2v per step the ADC requires.

I'm assuming my logic is wrong, what would be the right calculation that corresponds with the specifications written in the schematic?


texts: Most efficient two-way switch relay and/or schottky (or..)

texts:
Scenario: On my old military Land Rover I have a three-way pole switch which turns the pilot and tail lights on (top position), or also turns on the headlights (bottom position).

Top: Pilot and rear lights ON
Middle: All lights OFF (unconnected terminal)
Bottom: Side and rear lights + Headlights ON

The challenge is:

to use as little relays as possible (ideally only one) due to space constraints. My fuse/relay-box is already too full.
headlights must be powered through a relay (currently they are wired through the switch, which is a known problem on older Land Rovers (burnt out switches, poor lighting)
pilot lights may be powered directly (i think -- they take 8 watts max alltogether)
I have a tried a Schottky diode as it seemed to provide a solution for having power flow in only one way, but when I'm measuring I detect that voltage does leak in the wrong direction (???). I use the SB550 5A 50V Schottky diode and placed it between the terminals on the switch itself (not as depicted below after the relay, but I don't think that matters).

So, this is what I got so far (the connector on the image leads to the lights):

I am not that experienced with circuits, I hope someone here can review my schematics and provide some ideas or feedback on how to improve on it.

Soo many thanks!


texts: 12 DC Power 3.5A to TV via Antenna Cable

texts:
I am looking for a single connection to a TV which is powered by 12Vdc 3.5A Max, I would like to power the TV via the coaxial cable and also use the coax cable as an antenna input.
I am looking for two separate circuits to accomplish the following.. using a common cable from antenna running to several other TV's coupling 12VDC on that cable without affecting the other TV's then running the coax with RF to another TV, decoupling the 12VDC which will power that TV via a separate connector and then continue to use the cable to the TV for antenna input..


texts:
I am having trouble getting a simple PWM output to work at all on a PIC32MX775F512H. Looking online, this seems to be all I need to get something working:

int main(void)
{
    SYSTEMConfig(SYSTEM_FREQ_HZ, SYS_CFG_WAIT_STATES | SYS_CFG_PCACHE);
    INTConfigureSystem(INT_SYSTEM_CONFIG_MULT_VECTOR);

    OpenOC1( OC_ON | OC_TIMER2_SRC | OC_PWM_FAULT_PIN_DISABLE, 0, 0);
    OpenTimer2( T2_ON | T2_PS_1_1 | T2_SOURCE_INT, 0xFFFF);
    SetDCOC1PWM(0x4000); // 50% duty cycle

    while(1)
    {
    }
}

However, the OC1 pin (pin 46 on the 64 QFN package) doesn't seem to be doing anything.


texts: Speakers Power and Quality Difference Factor

texts:
I started tinkering with speakers (mostly amplifier circuits) and I learned a lot about how sound and amplifying works but I don't understand how to increase quality

I have several kind of speakers , 0.5W , 1W , 5W but some speaker's quality better than others , I don't understand why ?

Their rated power is same , resistance same , size is same but sound quality different why ? (Both of them almost never used before and no visible damage )

I know my question seems like off topic but I want to know what's determining quality (factors or reasons)

Like quality depending on amplifier or speaker (maybe both ?) And what makes two same sized & power speaker better than each other ?

Edit : I want to make myself clear , When I say "quality" I don't mean noise or spikes . I mean audio sounds better (like it's more similar to real life voice)

For example : My cousin bought sennheisher headphones (I'm not advertising brand ) and when they stop working he gave them to me and I noticed internal speakers are almost same as mine but somehow mine sounds worse , why ?

Also I'm sorry if my question so hard to read because of grammar errors


texts: Exceed recommended power supply range on analog switch

texts:
I would like to use an analog switch in my design (NLAS5223C).

The recommended power supply range is up to 4.5V, and the absolute maximum rating is up to 7.0V (relevant specs attached below.)

I'm wondering, if it safe to use this device with the power supply rail at 5V.

I'm sure the official response from On Semiconductor would be that I shouldn't use this device above 4.5V, but I'm wondering what is the effect/risk of exceeding this limit, especially in this particular case of 0.5V.  I've also posed this question to On Semi - no response yet, but I'll update here if they do get back to me.

I'm also curious what's happening to the device internally, and if there's a way to quantify the effect / risk.

Note: I intend on passing analog signals from 0-5V through the device. This device does have internal ESD diodes, but I'm assuming that the clamping diodes are relative to the power supply rail, and therefore shouldn't impact the analog signal.


texts: Replace copper capillary thermostat with digital temperature controller relay

texts:
Our lab has an old New Brunswick Model G25 incubator shaker. Its temperature control function is broken lately. We would like to replace the two copper capillary thermostats with modern digital temperature controllers. Such as this one on Amazon.

I found its manual. On page 32, it has the circuit diagram. I found an RCAS bridging the "control" thermostat 1TAS-2 (pic 1). In the manual of another similar model, I learned this is a resister capacitor in series circuit (1mF+100Ω, pic 2).

My questions are:

What is the purpose of this bridging RCAS design? To provide a low constitutive current to the heater circuits? To prevent spark or surge from the thermostat?
Will it affect my attempt to replace the capillary thermostats with digital controllers?

Thank you very much. I have rudimentary electrical skills. Any suggestions on this project will be appreciated.


texts:
I just got a 4 chained 8x8 LED max7219 displays with a 5 pinout, these are very popular
https://www.amazon.com/Wangdd22-MAX7219-Arduino-Microcontroller-Display/dp/B01EJ1AFW8/ref=sr_1_5?s=books&ie=UTF8&qid=1520880134&sr=8-5&keywords=MAX7219

I've seen several ESP8266 tutorial projects using these that are using onboard 3.3v output, everything plugged directly into the LED display.
Here is one: https://www.youtube.com/watch?v=mn9L85bhyjI

However the max7219 spec sheet says 5volts, and I see nothing about it supporting 3.3v.

So far, I've gotten them to work fine with the +5v from the Arduino directly connected. They also work with the +5v on the raspPI, but it has locked up a few times (I read the raspPi has a hard time running more than 2 displays without external power to the display).

My question is:

How/Why does it work on 3.3v? Is it safe to operate it this way? If not, what can happen? Is there a better (e.g. "more proper") way to wire it to a ESP8266?

Thanks!


texts:
I've designed this H bridge to control electromagnets using an arduino. I wanted to know if I've made it right, or there's something that can be improved.

Thanks for your time.

Update 1: Vcc is 12V and P1-P2 voltage will be arduino signal so 5V.
The thing is that I want to controll all four mosfets with only two signal ports.
Also I don't know that much of electronics.

This is the new design

Thanks for your support


texts:
BACKGROUND
I have a panel with light indicators (LED) in RED,GREEN and YELLOW. Since the eye have different sensitivity to different colors, some colors must be brighter than others to be percepted as the same power (brightness).

QUESTION
LED's light emission are in mcd (milli candela). If, lets say RED is 1, in what ratio do I need to select GREEN and YELLOW so they are percepted as the same power (brightness) as the RED one?


texts: Ordinary LED response to nanosecond pulses

texts:
Can anybody explain to me the output waveform generated on pins of an ordinary LED when it is exposed to very short light pulses?

I can clearly see that there is a precise difference in the length of the response by 55ns when the led is exposed to 110ns pulse instead of 55ns pulse. However the overall length of the waveform is much longer and there is a sharp pulse followed by a dip about 400ns later.

55ns light pulse response

110ns light pulse response

100us light pulse response

It seems that there is a rapid negative response first and then the expected voltage spike hundreds of nanoseconds later.

What are the mechanics of this?


texts:
How can there be a current flow when back emf equal and opposite of suply voltage? Isn't there a cancellation of voltage to zero volts? I have attached a video regarding this. Please answer this intuitively, I have already wasted enough time on this but couldn't find satisfactory answer.

https://www.youtube.com/watch?v=ae0fy435zJA


texts: Some issues modeling a "two terminal source" coupled to a differential amplifier in LTspice

texts:
Below is a circuit where on the left there is a floating single-ended source which directly couples as an input to a DC differential amplifier:

So the idea is to be able to simulate a real scenario for a single-ended floating  source to a differential-ended inputs of the above amplifier. The source has single-ended outputs but has balanced output impedances as Rs1 and Rs2.

If the source were a bipolar output it would also have a ground which wouldn't be a problem.

But in this case imagine the source is like a battery, which has only two leads. It doesn't have a third lead to connect to common ground of the circuit.

As you see above in DC analysis Vin is increased from 0V to 100mV.

I'm having the following plots:

For the red source output differential voltage (Vin+ - Vin-), LTspice  outputs not really a linear plot. There is some sort of nonlinearities.

And if we check Vin+ and Vin- wrt ground (blue and green plots at the bottom), we even see a much nonlinear crazy plot.

But the output Vout is very linear.

My questions:

1) Are those crazy plots for Vin- and Vin- common-mode voltages that the program creates since the source has no ground? But Vout is very free of problem. Is that because the common-mode noise rejected perfectly in simulation?

2) Will this way of coupling(without any use of ground for the source) work in real? I mean wiring exactly like in my schematics.

3-) How to implement this properly without converting the source to a bipolar source and get similar results as in real? I mean in simulation I still want to see the source as two terminal source without any ground but the simulation will work. How to do that?


texts: Precision half-wave rectifier / peak detector oscillation on positive cycle

texts:
I am having trouble building this precision half-wave rectifier to use to detect an AC peak on a real PCB:

The "real" circuit uses an LM318 opamp,  but in LTspice the LM308 appears to replicate the problem ok.
The problem I am having is the output opamp_out, where the circuit is oscillating:

This answer seems to provide a hint.
Interestingly, this occurs only on a PCB; on the breadboard the circuit behaves cleanly.
I have found that stray capacitance from the network at Vin- to GND (C2) causes the problem to be very bad. This might be the cause on the real PCB due to the ground plane:

Things that appear to mitigate:

Reducing R1 & R2 (discharges C1 too fast)
Putting a capacitor in parallel with D1 (peaks are no longer at the top of the sine wave)

How can I mitigate this problem on the PCB?


texts: Average current mode control compensation

texts:
This is the structure of average current mode control (source here).

Please look at signal \$V_{com}\$ at the positive input of PWM modulator.
For proper operation, in steady state the magnitude of \$V_{com}\$ should be in range peak to peak of ramp signal. Is there a clear procedure (almost like step by step) to guarantee this?

I tried to simulate this and even using simple integral compensation but \$V_{com}\$ is always out of range of ramp signal.

This is my simulation result with target 3V input and 2V output.


texts: Can someone explain the mysterious non-behavior of the DAC0808 and DAC0832, is there a difference between them on the output side?

texts:
So I have been very happy successful with my R-2R network ladder DAC powered by 74LS245 or similar bus transceivers, with 1% resistors, for nearly perfect output voltage going from 0 to +5 rail, with pretty good precision. Enough to produce voltage ramps to drive the X and Y inputs of my oscilloscope to produce a pretty decent raster display.
But I wanted to learn how to use a proper DAC chip and compare if perhaps the precision I can get with those might be better, and the space it takes up on the board. I have here the DAC0808 and the DAC0832. I know the '32 has some magic with dual latches on the digital side where one can stage the new input while the previous value is presented on the analog side, and then instantaneously activate the new stabilized (latched) value, etc. That digital stuff is easy for me to comprehend and control.
I'm pulling my hair out over the apparent complexity of the analog side of these two DAC chips. I cannot make this work for the life of me and I am flabbergasted about why this is so complicated.
First, all datasheets are telling me to use an external OP-amp. I understand why I would need that to drive a load, but I don't care about load right now, I have a high impedance load on my scope, and just reasonable voltage is all I want to see right now. Besides, if I have to add an op-amp I am already using up nearly as much space as in my home-brewed ladder-DAC.
Besides, I have already established that just any op-amp might not have the frequency characteristics that I would want aside from the hassle of procuring one that doesn't have voltage loss, if it can deal with a single GND-Vcc supply without needing negative power rail. So much hassle!
But there is intricate magic going on with these 4 inputs and outputs that I have been searching all over to find someone who explains it to me real slow, and found nothing.

+/-Vref
Rfb
Iout1
Iout2

it appears that the principle is somehow not voltage but current based, but frankly, I just don't understand it. And why is it so complicated?
All I want is to have the DAC produce output between the 0 and 5 V digital rail. Isn't there some minimal circuit that does just that? I have seen some, and only in passing on video, and when I build it I get nowhere, because I don't understand why it is like that to begin with?
Here is an example of such an in-passing shot of a simpler circuit, but then the guy shows me how he programs his stupid Arduino, and I don't care about the digital side.

If you don't want to explain it yourself, but you know a good tutorial introduction page I can read, I would much appreciate it.


texts: i-v graph, how to find current and its behavior

texts:
I have this circuit and I am trying to make a i-v characteristic chart.  I see that it has 2A as displayed, so would I split it between the 4 ohm resistor and the left side element?

In addition, I am confused at exactly what I am supposed to graph based on the resistors shown.


texts:
I have ordered these stepper motors. I asked the seller how many revolutions the motor can achieve in a minute and they answered 43. I calculated (13 + 212/289) * 200 * 43 / 60 to determine how many steps I would need to step in a second to achieve 43 rpm. This results to roughly 1950 steps per second. However, when I try to run the stepper motor with 1950 steps per second, it stalls. It vibrates but doesn't turn. After reducing the steps per second to 1300, the stepper starts moving again.

I'm using TB6600 drivers from eBay, set to ignore microstepping and to supply 0,5 A current with 12 V. I'm controlling the driver with an Arduino Mega 2560 and AccelStepper library.

Why can't I run it with higher speeds? I've had this problem with other steppers, too.


texts: Sourcing parts for Really, Really low frequency filters

texts:
I'm doing a project at work that has a couple of esoteric requirements, particularly for a 0.1 Hz (0.07 Hz really, due to part availability limitations) Highpass filter (in the data acquisition system).

Right now, I'm using a 22uF film cap, and 100K resistor, and the whole affair works quite well. However, the film cap is enormous (1.240" L x 0.532" W), and the resultant PCB is really a very large (there are many channels).
I really don't want to go too much higher for the R in the filter, since it's going into an op-amp. With the existing system (OP27, need the really low 1/f knee), +-10nA bias current, you get \$10*10^{-9}A*100,000\Omega = 0.001V,\$  or 1mV of offset due to bias current.

WIMA used to manufacture some compact 22uF 16V film caps, but they have EOLed them without a replacement.

Unfortunately, the application is a bit extreme. The caps need to be able to handle extremely low temperatures, and hard vacuum, which I think means electrolytics are out.

Does anyone manufacture large, low voltage film caps (voltages in question are +-5V, nothing major)? Alternatively, does anyone know how electrolytics fare in vacuum?


texts: Multiple Voltage Switch Mode Power Supply

texts:
Building a multiple voltage power supply for an extremely harsh environment.  Will be in a factory type environment with heavy equipment.  Looking for a sanity check on the schematic and board and any advice you may have to strengthen the device.

Schematic

(source: stealthmicro.com)

Board Layout

(source: stealthmicro.com)

Or if you would rather download the eaglecad files to look at them that way.
http://www.stealthmicro.com/files/Power-Supply.zip

Any help or suggestions would be greatly appreciated.


texts:
I want to create a SR latch using 7402 IC. I would like to read the output (i.e. Q value) from the IC using an ADAM-6066 which has the following specs for digital input:

Wet contacts: Logic level 0: 0~3 VDC Logic level 1: 10~30 VDC

My question is:

Does the 7402 IC have open-collector output? The datasheet says nothing.
If the 7402 IC does not have a open-collector output then can I connect A SN7407N IC to the output of 7402 IC and pull up the voltage from the output of SN7407N IC to 10-30VDC?

I look forward to your suggestions.


texts:
The schematic below is for an analog front end that takes in various different voltage waveforms and scales them down to an acceptable level for an ADC. At the very end, before the ADC, U6 (LMH6551) converts the signal from single ended to differential.

The problem happens when the relay is switched on (from attenuation x0.024 to no attenuation x1). When the relay is on, the gain of the variable gain amplifier (U5) is much lower than what is expected. When we tested, we made sure that the voltage into the input of U5 is the same when the relay is off or on. We also made sure the voltage into the part was low enough not to clip. U5 works well when the relay is off.

We tested the issue with R11 removed, with U7 removed and connecting AttenOut to R9 directly and measuring U5's preamplifier output. In all cases, the gain was not correct.

We are using the STBB1-APUR to generate the 3.3V rail and the LM27761 to generate the -3.3V rail (from a 5V USB input). Both of these voltages are fine when the relay is on or off.

Any help or feedback would be appreciated!


texts: frequency allocation for telecommunication companies

texts: For a high bit rate in data communication we need a high bandwidth. Suppose there are hundreds of carriers in a particular region and they are all allocated microwave frequencies. Minimum spacing rules are also applied during frequency allocation. Due to this the resultant bandwidth, that each carrier gets, reduces. So because of this the resultant bit rate would also decrease if we consider the shannon-hartley theorem. Then how do carriers claim to have high-bit rates? Is there a different way through which frequencies are allocated?


texts: Finding transfer function by linear system

texts:
Here's the system:
$$\begin{cases}
 z(t)=h_1(t)*x(t) \\
 w(t)=z(t)+h_3(t)*y(t) \\
 y(t)=h_2(t)*w(t)
\end{cases}$$
And
$$\begin{cases}
 h_1(t)=\exp(-3t)u(t-t_0) \text{, with $t_0$ positive} \\
 h_2(t)=\exp(-t)u(t) \\
 h_3(t)=\exp(-5t)u(t)
\end{cases}$$
I want to find transfer function \$Y(s)/X(s)\$ by Laplace transform. So I've tried it and this is what I've got so far:
$$
\begin{align}
Z(s) &= H_1(s)X(s) = X(s)/(s+3) \\
W(s) &= Z(s)+H_3(s)Y(s) = H_2(s)W(s) = \frac{X(s)}{(s+3)} + \frac{Y(s)}{(s+5)} \\
Y(s) &= H_2(s)W(s) = \frac{W(s)}{(s+1)}
\end{align}
$$
I can't seem to find \$Y(s)\$ and \$W(s)\$ values, because when I replace \$Y(s)\$ with its value in \$W(s)\$ function, \$W(s)\$ will eventually be cancelled out and so \$W(s)\$ will never be found, same goes for \$Y(s)\$. Is there something wrong so far or else what can I do to find \$Y(s)/X(s)\$?


texts: What can be used for impromptu EMF shielding?

texts:
I have a robot with a lot of servos in close proximity and a high-current DC motor powering an airsoft gun. The motor is causing electromagnetic interference with the servos, and we need to shield it somehow. The problem is, we're at a competition, so we need something that can maybe be bought at a convenience store.

Can aluminum foil be used for EMF shielding, and if so, would more layers be better or worse? What else could we try to use?


texts:
My task is to gather measurement from peripheries of STM32F4 on SDCard and I started reading about this. Could you double check if I'm correct:

Single block memory on my SDCard is 512 bytes, so before I would write anything, I should gather 512 bytes of data (otherwise I will waste the rest of block).
To do that, I need to write queue. I deceided to create DMA in fifo mode, to transfer from flash to SRAM, and in DMA interrupt use FatFS function to move it to SDCard.

And my second question, what would be the best option, when gathered data will trancend 512 bytes (ex. before loop execution there are 510 bytes of data and there comes new 10 bytes). Is DMA functionality provide itself or I should prevent it someway?


texts:
I want to build a thermostat and I'm not sure what power resistor to choose. The thermostat will be build inside a broken microwave oven. The resistors will be connected to 230V AC and they will be controlled by an arduino pro mini for AC PWM using a triac + other components.

I'm thinking to go for 2 or 3, 50W 1.5k ohms power resistors connected in paralel.This is how they look: https://www.tme.eu/en/details/ax50wr-1k5/50w-resistors/te-connectivity/1-1625984-9/

According to my calculations, I will have:

I = 230/1500 =  0.153A

P = I x V = 35.19W

So 35.19W is ok, given that the resistor maximum power is 50w. But in the data sheet is mentioned that without a heatsink the maximum power drops to 20W.
So I don't know how the metal plate of the microwave oven would compare to a heatsink. It would be safe to use these resistors?

I want to make fermented yogurt from bacteria. So I need a temperature between 40-45C so that the bacteria wont die. Also, in the instructions, it says that in order to make ticker yogurt, it would help to keep the milk at 70C for 30 mins. That's why I'm doing it. But in the future, I might use it for other things as well.


texts: Stereo to High Speed LED for Data Transfer

texts:
I am currently doing a project on optical data transfer using LED. The first hurdle I need to overcome is the LED driver circuit. I have little to no background in circuits. I do know a fair amount of relevant coding stuffs for this project (on the demodulation side at the receiver end)

My preliminary setup would be a stereo output from a PC and this stereo will be the input on my LED driver circuit.

The question is, how should I approach this design to achieve at least 1Mhz pulses of phosphor-based White LED's? Since the input is analog, I need an ADC so that the signal will go to some microcontroller or IC and drive the LED ON/OFF rapidly. One consideration is to have a PWM driver that can deliver at least 1Mhz pulses.

Thing that need not be considered now is
- possibility of data that causes LED to be OFF for a noticeable period

Goal:1. Translate a stereo input data to a high speed LED ON/OFF's sequences.2. LED intensity should be consistent. (ie. the Photodiode that receives the light should output similar results each time assuming the data transmitted is the the same)


texts: LiPo balanced charging circuit from USB, controllable by a Raspberry Pi

texts:
I am building an RC car controlled by a Raspberry Pi, and I'm not sure how to go about setting up the power delivery circuit. I plan to power it with a 5200mAh LiPo battery, 2 cells, 50C rating @ 7.4v.
It has a JST-XH plug and Deans (T) connector for charging, and I would like to make it so that the vehicle can go to its designated charging place by itself and charge wirelessly. For this, I thought an easy way to do it is with a Qi wireless charger and a Qi receiver with USB-C.
With these in mind, I would need a circuit able to charge the mentioned battery without it catching fire, while also providing power to the Raspberry Pi while it stays in a low power state and the possibility to read battery percentage from it.
I have searched for something like this on the web but I didn't have any success. I have no background in electrical engineering, but I'm willing to learn if it means I have to design my own circuit.
I would also appreciate any feedback with my approach and any alternatives.


texts:
i would like to know if anyone of you recognize these 2 materials and what they are used for ?

A material sticky on one side normal on the other , used between capacitors and aluminum enclosure .

A material consisting of 2 parts face is like card board and second part is like thick butter paper. IT is used between 2 pcbs stacked over each other .


texts: Can a LC tank circuit amplify frequencies beyond the bandwidth region?

texts:
The LC tank circuit in a class C amplifier has a specific resonating frequency of 1/(2piLC). Depending on the Q factor its frequency may vary inside its bandwidth.

Does this mean my class C amplifier can only amplify input signals with frequencies inside the bandwidth region?

I read that bandwidth is the region where the power is more than half of the power of the center resonating freqeuncy:
$$BW=f_2 - f_1$$

BUT it does not say it cannot accept frequencies outside this region. So can it accept frequencies outside the bandwidth?


texts: For maximum EEPROM readability into the future is it better to write once and leave it, or periodically "refresh"?

texts:
What is the best strategy if I have a static value that I want to store in EEPROM once and then be able to read it as far into the future as possible?

Is it better to write it one time and never write to it again, or is it better to periodically (like once per decade) re-write the the value back to the EEPROM to "refresh" it?

Speaking here about modern EEPROM, specially on-board an ATXMEGA which is rated for 100,000 cycles/100 year retention at 25C.

Asked differently, is that 100 year retention specification from the time the the EEPROM is first written to, or from the time the EEPROM was most recently written to?


texts: wiring Tamura 4 pin hall effect current transducer to differential daq

texts:
How do i wire a 4 pin hall sensor:
200A model below

https://www.mouser.com/datasheet/2/397/L03SXXXD15-469349.pdf

I don't understand the wiring schematic below

I currently have +15 to pin 1, -15 to pin 2, V high from das to pin 3, Vlo from das to pin4.  Power is from a regulated power supply. The only way for me to get reasonable data to the das is to jump the 10k ohm between pin 4 and -15.  Is this correct?


texts: Low cost, wide bandwidth voltage reference

texts:
I have designed a circuit with 5V single-supply op amps, but since the inputs to the circuit are AC, I need a biasing voltage to replace the ground node on the equivalent dual supply circuit. Without getting into unnecessary circuit details, this biasing voltage may need to sink or source up to 10 mA.

The circuit amplifies signals of around 2 MHz, and originally I had used a wide bandwidth voltage regulator (TI TPS71701) to generate this biasing voltage, but I found out the hard way that this regulator is unable to sink current.

I've also tried using another, non-wide-bandwidth regulator (Diodes Inc. AP2202K), which did appear to work, but its datasheet makes no mention of being able to sink current, so I don't intend on relying on an undocumented feature.

Also I've tried using a low speed (1 MHz GBW) op amp (TI LMV342) configured in unity gain buffer topology. Although it does appear to work in practice, SPICE simulations indicate that there should be large (100 mV+) output voltage swings when sourcing/sinking a few mA of current at 2 MHz, which is unacceptable in this circuit. These swings disappear when frequency is reduced to 2 kHz. Hence I'm a little hesitant to put this into mass production.

I'm looking for suggestions of other low-cost circuits capable of generating a 2 V reference from a 3 V or 5 V supply, and which have no problem sourcing and sinking currents up to 10 mA at 2 MHz with little loss of regulation.

EDIT: I tried adding a load resistor to the output of the TPS71701 regulator, such that the amplifier circuit is able to sink current through this resistor. This did work, but now I have a constant 10 mA load (and this is a battery powered device). Actually, when in use, this product draws on the order of 1 A, so 10 mA might not be so bad, but still, I'd feel better with a circuit without a vampire current draw.


texts: How do I use multiple BCD switches as a single binary input?

texts:
I'm trying to convert a 4-digit (decimal) number to binary. My input is a BCD switch (this one). I've been looking to see if I can find either a logic-based circuit or a specific decoder IC to convert the values off of the switch array into a single binary number. I don't seem to be having much luck though.
Is there a good way to do this wither with some sort of converter or with logic? I'd appreciate your thoughts.
Thanks!


texts: Can't understand what multiplexers do in CPU datapath

texts: I'm currently learning about data path in a CPU and having a hard time understanding the functionality of G,L, H parts in the following image. Why have those parts been used there?Thanks in advance.


texts:
This is a general question regarding Atmega328P.

While I was reading the datasheet of Atmega328P, I see that it has Ports B, C, and D.

So, I'm surprised to see that there is no PortA.

Is there a specific reason for it?

Datasheet for Atmega328P: http://www.atmel.com/Images/doc8161.pdf


texts:
In most power supply designs either it's a bench PSU or LED driver etc, manufacturers use solder to increase current tolerance of the PCB trace:

Is it a valid choice or it's just to save money?
What are the disadvantages of doing this?
How much current can solder tolerate?
Does the resistance of the solder affects the circuit?


texts: My company does audio visual services.  When we use a single 120/208 VAC Three-phase "Y" power source for lighting, audio and video we get noise caused by the lighting dimmers injected into the audio and video.  We purchased a 30 KVA Isolation transformer.  We tie-in power and run it first to the lighting dimmers then put the isolation transformer in line before powering up the audio and video equipment.  It eliminates buzz in the audio and interference lines in the video.  The transformer has three hot and one ground connections on the input side (no neutral on the input side) and on the output side a ground, neutral and three hot connections.  Is it correct for me to wire the input ground to the transformer case and wire the output ground to the output neutral and not connect the output neutral and ground to the case or input ground?


texts: Xilinx Vivado: [Common 17-53] User Exception: Unable to launch Synthesis run. No Verilog or VHDL sources found in project

texts:
I have a vivado project containing a Xilinx IP core. A tcl script was generated for this project and contains links to the IP core source. The .tcl script and IP source files (xml, xci and veo files) have been added to version control.

When I run the TCL script to create the project, it works fine. However, right-clinking on the IP in vivado and selecting "generate output products" in order to generate the synthesis files produces the following error:

[Common 17-53] User Exception: Unable to launch Synthesis run. No Verilog or VHDL sources found in project

Deleting and re-adding the IP files doesn't fix the issue.

How do I use the tcl script to include and regenerate IP sources?


texts: Understanding a visual description of a circuit (easy)?

texts:
I have a description of a circuit that is confusing for me as a beginner. I am also new to the site, so  please direct me to the appropriate place to ask this question if this is not it. Here is the situation (some unnecessary bits have been omitted):

  A capacitor (C1) is charged to a potential V by using a (DPDT) switch
  to connect one of its terminals to one terminal of a dry cell battery
  and its other terminal to the other terminal of the dry cell battery.
  The dry cell is then disconnected, and an initially uncharged
  capacitor C2 is connected to C1 via the DPDT switch as follows: one
  terminal of one capacitor is connected to terminal of the other
  capacitor, and the two other terminals are connected to each other.

Is the circuit consisting of the battery and the capacitor a series circuit? Or is it a parallel circuit? Is it always series/parallel, or does it change throughout the experiment?
I believe that this would be series, but I was told that it is actually in parallel. If so, how come?

Secondly, after both capacitors are connected, why is it that the voltage decays?

Thank you!


texts: I'm working on a project including usage of several smartphone built-in microphones. However, I have no idea what sensitivity (e.g. mV/Pa) should I expect. I haven't came across any manufacturer's specification that would reveal that info. And smartphones manuals never tell anything about microphones. Is there any way to find it apart from experiments?


texts: Problems when powering a circuit directly from Solar Panel

texts:
Am working on a project which uses Solar panel to power the project. I have a 12v 5w Solar panel to use for this purpose. And am thinking to remove the battery from this project since I feel that application of this project is not very critical and it's enough for me to work only when the sun is bright and shining.

Apart from the above what are the practical problems that I can face when attempting to power a project directly eliminating battery. Here is the circuit I intend to power it using Solar panel directly

Also I was wondering whether underpowering these kind of chips from panel in non optimal conditions might damage the circuit and it's components. Is it a right concern? How can I identify a particular chip is susceptible to get damaged by doing this?

So far I have made an estimation that my circuit will consume 300ma. Any advice or suggestions please?


texts: Bit growth handling for complex multiplier using Gauss' method

texts:
I'm trying to predict/handle the bit growth that occurs when implementing a complex multiplier using Gauss' method. I am looking to implement this multiplier in VHDL. The FPGA I use has a limited number of DSP elements, and so I anticipate that should I implement this multiplier correctly, it would reduce the number of DSP required per complex multiplication by 1.
Should A = (a+ib) have bit width m, and B = (c+id) have bit width n, then classically:
C = A x B = (a+ib) x (c+id) = ac - bd + i(ad + bc)
will have bit width of m + n + 1 for both its real and imaginary parts respectively.
Now, should I use Gauss' method of complex multiplication whereby only three multiplications are performed, namely ac, bd and (a+b)(c+d), then:
C = A x B = (a+ib) x (c+id) = ac -bd + i[(a+b)(c+d) - ac-bd],
Here, we'd find that the real part will have a bit width of m + n + 1 as before, but the imaginary part will now have a bit width of m + n + 3.
Please can someone confirm whether this is really the case (I've checked a few times but could be wrong), and then further give me an idea as to how to handle the additional bit growth in the imaginary term (since I require that it have the same bit with as the real).
Thank you in advance.


texts: How to select a single component in Altium Designer using the PCB filter?

texts:
Using the PCB Filter, how can I select a single component easily (not its primivites)?
Every now and then I have a complex component (such as an on-board PCB antenna which consists of copper traces, pads, keep-out regions, etc.) that I need to select by itself in order to lock/unlock primitives, for example. The problem I run into is once I've unlocked primitives, selecting the component again becomes a challenge due to non-component items (vias, polygons, etc.) scattered around that prevent selecting with a rectangle or lasso easily. Shelving polygons, hiding objects such as vias, and so on works, but is time-consuming.
(IsComponent Or IsComponentBody) and InComponent('AE1') is an expression that worked, but is there a simpler one?
(Altium Designer 20.1)


texts: DALI: Handling multiple responses from DALI system

texts:
I designed my own DALI devices and now trying to build-up a DALI system. Since my DALI gears are based on MSP430G2553, I took advantage of code being already done for TI's DALI demonstration board.

Source code
Application note

Right now I'm working only with one DALI master and one DALI slave. Question is, how will (or how should) the system behave with more DALI slaves.

My point is... How to handle multiple DALI responses, e.g. after broadcasting the QUERY STATUS command? I suppose that all devices in the system would try to send their response, not knowing that there are more slaves trying to communicate. What is the work-around for this case?


texts:
I am trying to select an appropriate solid state relay for a project using an ESP8266 microcontroller (from 3.3v gpio pins). I don't know much about them, but I assume the key parameters are:

Maximum load parameters (current and voltage)
Minimum/maximum control parameters (current and voltage)

Take this http://www.mouser.com/ds/2/315/semi_eng_pd1a_aqy27-1075857.pdf as an example.

WRT to max load, it looks good: 60V/2amp continuously is more than I need.

The control parameters is a bit more confusing... On page 2 the datasheet lists a number of fields next to 'input'. Is the one I want for the control 'LED dropout voltage'? It looks like that says the maximum control voltage is 1.5V (above the 3.3V GPIO logic level coming from my microcontroller). Also, it looks like the 'recommended current' is 5-10mA (which is fine for the 12mA GPIOs). Can someone help me out with this part?


texts:
I have a very basic and rather silly question which I have not found any suitable answer yet.

Suppose I have 2 transmission lines. One carrying a high frequency sinusoidal signal. Is there coupling in a 2nd transmission line close to the 1st one if:

1) The second transmission line is an open circuit?

2) The second transmission line is properly grounded?

Will there be a potential difference between the edges of the second transmission line in either case?

If NO, then why and if YES, then will it result in reverse coupling?


texts: Can't flash big binaries using dfu-util/pydfu to STM32H743VIT6

texts:
I have a board that uses STM32H743VIT6 (same as OpenMV4) that I can't flash binaries bigger than (500-600KB) to it although it has 2MB of flash.
Smaller binaries seems to be flashed OK, I am using the USB port of the STM32H743 with BOOT0 pin toggling and using dfu-util and pydfu (micropython implementation).
Any idea what might be wrong?
With pydfu an error appears around 700KB:
$ make BOARD=BOARD_1 deploy
Writing BOARD_1/firmware.dfu to the board
python3 ../../tools/pydfu.py --vid 0x0483 --pid 0xDF11 -u build-BOARD_1/firmware.dfu
File: build-BOARD_1/firmware.dfu
    b'DfuSe' v1, image size: 959405, targets: 1
    b'Target' 0, alt setting: 0, name: "ST...", size: 959120, elements: 2
      0, address: 0x08000000, size: 20560
      1, address: 0x08040000, size: 938544
    usb: 0483:df11, device: 0x0000, dfu: 0x011a, b'UFD', 16, 0x56f7fb3b
Writing memory...
0x08000000   20560 [=========================] 100%
0x08040000  938544 [====================     ]  83% DFU: erase failed (STATE_DFU_DOWNLOAD_BUSY)
Makefile:571: recipe for target 'deploy' failed
make: *** [deploy] Error 1

A failed flash in dfu-util just gets stuck around 700KB:
$ dfu-util -a 0 -D firmware.dfu
dfu-util 0.9

Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2016 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to http://sourceforge.net/p/dfu-util/tickets/

Match vendor ID from file: 0483
Match product ID from file: df11
Opening DFU capable USB device...
ID 0483:df11
Run-time device DFU version 011a
Claiming USB DFU Interface...
Setting Alternate Setting #0 ...
Determining device status: state = dfuIDLE, status = 0
dfuIDLE, continuing
DFU mode device DFU version 011a
Device returned transfer size 1024
DfuSe interface name: "Internal Flash   "
file contains 1 DFU images
parsing DFU image 1
image for alternate setting 0, (2 elements, total size = 959120)
parsing element 1, address = 0x08000000, size = 20560
Download    [=========================] 100%        20560 bytes
Download done.
parsing element 2, address = 0x08040000, size = 938544
Download    [====================     ]  82%       777216 bytes^C


texts:
After going through multiple youtube videos and some articles I'm still having trouble imagining voltage.

If we measure across a battery's terminals we will see electrical potential. This is caused by the collection of negative particles on the negative terminal and positive particles on the positive terminal. Since these are being "kept apart", there is some work being done to hold them where they are, and therefore potential energy. The difference in potential energy between the two terminals is our voltage.

When we connect a battery to a simple circuit consisting of a lamp (for example), we can measure the two points on the conductor using a voltmeter and see 0V. Since the electrons are being "pulled" towards the positive terminal (in the same sense that gravity pulls a dropped object downward), there is no work being done to prevent the from traveling to the positive terminal, therefore the difference in the potential energies between the two points is 0.

Now when we measure across the lamp in the circuit we will once again see a voltage. I think this is where I get confused. The lamp isnt part of the conductor, and therefore there is voltage - this is where my book leaves off.

Using my reasoning from above - is this because on the positive end of the lamp, it's connected to the positive terminal and has a higher positive charge than the rest of the conductor? This would explain why there is a measurable potential difference. If so, what happens inside of the lamp with the potential energy? Some of it must be turned to heat?


texts: So, I was going through the spec sheet of super bright 5mm orange LED, and it was listed that the forward voltage is between 1.8V and 2.5V. Below that there was a property listed as 'typical voltage' and had a value of 3.2V. I'm confused as to what value of resistance I must use.


texts: Moving Ground in between resistors in series

texts:
What happens when you move Ground to the given point? How does it affect the Voltage and the Resistors after moving it in the circuit?

Missing values:

.Current (I)= 30mA
(V.R1)= 15V
(V.R2)= 3.6V
(V.R3)= 10.7V
(V.R4)= 10.7V
(V.R5)= 12.6V
(V.R6)= 7.4V


texts: How to get Voltage gain from a cascaded transformers?

texts:
I am solving a problem from Fundamentals of Electric Circuits Chapter 13, Problem 65.

I know how to solve it using mesh analysis, on the other hand I am looking for a simpler method, so I am trying to use the idea used in Miller approximation,so I can get rid of the 40 ohm (feedback)resistor, but I can't get the voltage gain for this port as It depends on the input current.

I stuck with  Vout/3 + 2 Vin = 25 Iin

My questions are:
How to get the voltage gain?
Are there any other methods to simplify the circuit?


texts: Simple measurment of resistance with microcontroller

texts:
What is a simple way to measure resistance (in this case 0-100 kOhm) using micro-controller (I'm using STM32, it has 12-bit ADC, timer, but no comparator). I want it simple (not too many components) and cheap.

The first idea I had was to use ADC with voltage divider. However it brings down the problem to measuring voltage across known resistor what is hyperbolically dependent on the measured resistance, so actual precision varies greatly over the range of values of unknown resistor. It also requires the known resistor to be much smaller value than known one, but this should be fine if big precision is not required.

Requirements:

Range: 0-100 kOhm
Precision: at least 1 kOhm, preferred <100 Ohm, but actually I am curious (thinking about - other possible applications which might require better precision) how high (with precision) we can get without making too complicated circuits.


texts:
I was thinking about buying a commercial griddle to use in my home to expand my cooking space but I found out that it has a NEMA 6-15 type plug instead of the typical NEMA 5-15 found in homes.  Since I rent my apartment, rewiring the outlet or similar work is not possible.  However since the 6-15 plug is rated at 240VAC, rather than 120VAC like the 5-15, I did not figure that it would be safe/possible for a simple adapter to be used.

Am I correct in thinking this or is there a workaround that would be safe and functional?

Cheers


texts: Can someone explain this high-speed P-channel MOSFET drive circuitry?

texts:
I found this circuit in an application note on P-Channel Power MOSFETS.

The note explains that modern technology has made it possible for P-Channel MOSFETS to approach N-Channel performance in power applications. I would like to make a DC motor driver that uses high-side P-Channels, but there is very little info out there on driving them at high speeds. This circuit looks promising, but I do not understand all of it.

Here is what I DO understand:

The two resistor pairs (Rh1/Rh2 and RL1/RL2) are use to set the amount of time each respective FET spends in the linear region (the time to charge up the gate capacitance). The diodes Dh/DL make it possible for the Rx2 resistors to set the rise time and Rx1 + Rx2 to set the fall time. The diode is orientated this way because it is almost always desirable to have a longer fall time than rise time.
The zener diode Dz somehow clamps the gate-to-source voltage within an acceptable range, regardless of the supply voltage.

Questions I have:

How does the capacitor Ch and the resistor Rz switch the FET on and off, and will this work for a range of supply voltages?
How does the zener Dz clamp the voltage in the acceptable range for gate drive?
Can this circuit keep the MOSFET enhanced or depleted indefinitely, or does it require a pulse every-so-often to deal with Ch?
What would the gate drive IC look like? Is this application referring to a micro-controller or something more current-capable? If a specialized driver IC is required, what are some example parts that could work, and what voltage range must they provide to Ch on the high side?


texts: Can someone explain this constant current load circuit?

texts:
I'm currently a rising junior in EE and I was just wondering if anyone could help explain this circuit for me. The purpose for this is because I need to learn how to build a discharger (constant current load PCB) for my school's solar racing club. I have little to no concept of upper-level circuit knowledge, I just know the basics of circuit analysis i.e. not how transistors really work, advanced calculations beyond nodal/mesh analysis. If anyone could help me understand what exactly each part of this circuit does and how I should go about building for my own project, I would really appreciate it.

The specs for the battery pack of my solar racing club are as follows: 35 modules of 12 battery cells each. The nominal voltage is 126 volts and 3.6 per module. One module's capacity is 36 amp-hours. The pack trips at a defined undervoltage point of 2.5 and overvolts at 4.2. The purpose of creating a discharger is to discover modules that are lacking in capacity and to fix them.

Thank you in advance to everyone for the help, I'm pretty new on here and just want to learn as quickly as possible.


texts:
A bit of context: I'm working on a smart tracker watch for an 8 year old. A hobby project, and I'm looking for parts to use.

Anyways, that's not what I'm confused by. This is my first project, so please don't judge me if I've done something wrong. But I can't for the life of me figure out why these parts have more than one GND. One of them actually has upwards of 30. What the heck is going on here?

The part in question is from a WL1835MOD WiLink 8 from DigiKey. I've linked the datasheet here: http://www.ti.com/lit/ds/symlink/wl1835mod.pdf

It's a Wifi/Bluetooth combo, and the part shows up as two separate parts on Upverter. That's why sometimes I refer to it as 2 parts and sometimes just 1.


texts: How to find current and voltage requirements of an LED lamp / strip using a multimeter?

texts:
I have an LED lamp who's current and voltage ratings aren't written on the lamp itself. How do I find the required input current and voltage to this lamp before powering it, using for example a multimeter?

For context: I have an LED driver that produces voltages between 100 and 300 volts at a current of between 0.3 and 0.7 amps. I want to make sure that the lamp I am using with this driver doesn't require a voltage and current that is out of this range (either greater than or less the range provided) but I don't have access to the tech sheet. How would I do this?


texts:
I want to simulate some circuits with SSR component but LTSpice does not provide this. From Eagle and KiCad I learned I can create my own component diagram. I'm not sure if I can do this also with a SPICE Application, because there are differences between and diagram and the functional aspect that SPICE simulates.

I have chosen the following SSR Component: "Sharp S202 S01" Data-sheet: S202S01, reichelt.de.

The data-sheet offers the following diagram which looks to me like the internal circuit inside of the component. I think the Internal Connection Diagram is the functional circuit diagram which offers the same result as the standalone component S202 S01. I'm not sure whether I'm reading it properly.

How can I solve this SSR Simulation with LTSpice (SPICE), to control 230V AC circuit with a 5V DC circuit?


texts:
I am trying to use the cellular ram on the Nexys 4 FPGA development board. I am using Xilinx Vivado and would like a Microblaze soft core processor to be able to perform reads and writes. So far I have created the processor in a block design.

After much hunting through the internet I eventually found an external memory controller or EMC which I thought looked promising. How would I go about connecting the Ram up? I have created a HDL wrapper and tried connecting the ports of the EMC to the pins of the ram, however, there are more ports than I need. I can't find any examples of the Nexys 4 or for the Vivado EMC.

I also found that the Nexys 2 has an example of an onboard memory controller. I see that the part number is the same for the RAM. Would this be usable and how would I use it in conjunction with the Mircoblaze?


texts:
A combinational circuit only depends on present input values.
Why ROM is considered as combinational memory?


texts: What do the terms code coverage and functional coverage refer to when it comes to digital design verification

texts:
It seems that verifying a design is a more complex task than the actual design itself and takes a lot longer to carry out. We may even need to create testbench to very the original testbench that tests the DUT.

Anyway, there does seem to be a lot of terminology involved in this as well and at this point I only wish to know what is code coverage and especially functional coverage. These terms are also used with reference to SystemVerilog that I am trying to read about.

Edit:

Just one more question here. What is a "configuration" in systemverilog?
The book says "Generate configuration : Randomize the configuration of the DUT and the surrounding environment." What does that mean?


texts: Trying to switch between 12V and 5V, CD4066B analog switch

texts:
I want to switch between an output of 12V and 5V. I'm using a CD4066B (datasheet)

Here's the pinout:

This is my schematic:

When I build this circuit, I end up frying the IC. What am I doing wrong? What can I do to make this circuit work as desired?


texts: TTL to +/- 12V conversion - what's a better way?

texts:
The context here is the pilot generator for a J1772 EV charging station. The specification calls for a 1 kHz +/- 12 volt square wave with varying duty cycle. The output is sent through a 1 k resistor on its way out the door.

So far, two different solutions to this problem have been presented by the OpenEVSE community at large.

Solution 1 is an LF353 op amp driven by an unregulated bipolar 12 volt supply. The problem is that the LF353 is not rail-to-rail, and so the output impedance has to be adjusted to account for the reduced voltage. That works, but it's not compliant with the specification.

Solution 2 is to use analog switches, such as the DG303A to select between regulated +12 or -12 volts on the output. That works very well indeed, but the BOM for that is about $5 just by itself.

It seems to me that there ought to be a much, much simpler way to achieve it. The analog switch seems to me to be vast overkill given that we're simply selecting between two regulated voltage levels given a logic level input.

I've tried to use circuitlab to come up with BJT or FET based switching, but gotten nowhere. It seems to me like some kind of simple push-pull "amplifier" is exactly what the doctor ordered... isn't it?

One of my (perhaps laughable) attempts:

simulate this circuit – Schematic created using CircuitLab


texts: Circuit breaker wiring: put source current on side marked with X or side with switch?

texts:
I am trying to wire an electrical panel in a standard manner.

I have several automation devices that take 120 Vac power.  In order to protect them, I have purchased a 2-pole circuit breaker, Phoenix Contact TMC 72B 10A.  I am now trying to wire it to an outlet.  I plan to put the breaker on L and N of the 120 Vac source.

The circuit breaker's schematic is shown in the below image.  Pins 1 + 3 connect to an X, pins 2 + 4 connect to what looks like a SPST switch.

Questions

What do the X's mean?
Where should I put power inlet?  On pins 1 + 3, or pins 2 + 4?

Any additional advice is welcome, I am looking to comply with industry standards.  Thank you in advance for your help!


texts: Will the DC charger for the 2nd battery affect any peripherals while charging?

texts:
I am installing a Deep cycle AGM battery in my car with a DC to DC charger via a battery box. The battery box has some peripherals such as usb/cigarette lighter outputs inline with the normal current flow.
I was wondering however if the DC charger starts to charge the 2nd battery, while a usb device or peripheral is plugged in will this cause problems? As from what I have heard batteries are generally charged by pushing electricity through them in the opposite direction? Would the opposite polarity have an affect on the peripherals?  Or if the charger has a higher voltage then the battery to charge it would that voltage transfer to the peripherals, making them more then 12v outputs? and potentially causing damage?

The 2nd photo is the lid of the battery box and the highlighted green wires are the peripheral's circuit from the positive terminal of the 2nd battery to the ground of the box. Everything connects to the box's ground (usb ports, cigarette accessory, DC Chargers negative, 2nd Battery's negative) and the box's ground connects to the Main car battery ground. The car battery Positive comes into the box and through the DC to DC charger (25amp projecta), which comes out the DC Charger (Green wire from the bottom right gland) and connects to the positive of the 2nd battery. There is a switch between the positive 2nd battery terminal wire and the peripherals circuit (the 2 gold nuts, with thick wire to thin wire) and a 10amp circuit breaker before the actual peripheral components (black box with the insulated spade connectors).
My circuit diagram is roughly how I have wired it all together, with the joins being anderson plugs. I am adding solar soon. From my understanding I do not think there would be any major problems with the setup in terms of current, as I believe the peripherals would only draw what they are needing. But I am not sure if the extra voltage from a charger would change things or if there would be a backwards current present.
Any guidance would be appreciated.


texts:
I'm trying to identify the following modulation scheme being used to transmit a infrared code.  It looks like manchester, but there's some gaps where there's no transitions.
The code being transmitted is
in hex = 621da4
in bin = 01100010 / 00011101 / 10100100
there may be a check byte at the end too.  I've attached pictures of the beginning of the code, the end of it, and a zoomed out capture of the whole thing.
any help immensely appreciated!
beginning

end

zoomed out


texts: Further Understanding Optical Parameter of Image Sensors for Use In Spectroscopy

texts:
I’m attempting to build a spectrometer and I’m having difficulty assessing the performance of a particular sensor. I am a novice and other posts on this forum have helped me greatly but I still haven’t been able to arrive at an answer that makes sense. I’d appreciate any help in identifying where I am going wrong. My goal is to assess my photon budget by determining:

the sensor sensitivity in units of ,
the pixel well depth (full well depth) in , and
ultimately the sensitivity in .

Most sensors I’ve been looking at make it easy enough to calculate this (if I’m doing it right) but for various reasons I’m looking at trying to make the ThorLabs CCS200 work for this application. The datasheet for the sensor, Toshiba TCD1304DG, does not give the chip’s pixel well depth and only offers sensor sensitivity in [V/(lx∙s)]. I’ve found another site,  Avantes, that reports the pixel well depth and sensitivity for this chip in [photons/count] but when I try to calculate these values I end up with wildly different answers that I have little confidence in.

Here is the path I’ve been taking (assuming the incoming photon has a wavelength λ = 600 [nm]):

Knowns for the TCD1304DG chip (from the datasheet) and the CCS200 system:

Sensitivity:         160  [V/(lx∙s)] (page 3)
Pixel Saturation:    0.600 [V] (page 3)
Pixel Size:      8 x 200 [μm^2 ] = 1.6E-9  [m^2 ] (page 1)
Quantum Efficiency:  0.96 [e^-/photon] (at 600 [nm], graph on page 10) (EDIT, not actually Q.E. as pointed out by user1850479)
Resolution:      16 [bit] (ADC on CCS200 webpage)

Attempted Conversions:

Starting with sensitivity, the conversion from lux to lumen flux is straight forward: [lx]=[lm/m^2 ]. Lumen to watt is much more frustrating for a physics application. Assuming a perfectly narrow band of light at λ = 600 [nm] the conversion from lumen to Watt looks like either η = 431 [lm/W] for a Photopic conversion, or η = 56 [lm/W]  for a Scotopic conversion (Luminous Efficacy Tables). I don’t know which type of conversion to use for this application (neither result in an answer consistent with the values given on the Avantes site).  I’ll assume Photopic conversion for this post. That leads to:

So the equivalent sensitivity is 160 [V/(lx∙s)]  ∙  431 [lm/W] = 68,960 [(V∙m^2)/J] (which is equivalent to [V/((W∙s)/m^2)]).

The energy of a photon at λ = 600 [nm] is 3.31E-19 [J/photon]. Given the pixel size, the sensitivity becomes:

68,960 [(V∙m^2)/J] ∙ 3.31E-19 [J/photon] ∙ 1/0.95 [photon/e^-] ∙ 1/1.6E-9 [pixel/m^2] = 1.502E-5 [(V∙pixel)/e^-]

With a saturation voltage of 0.600 [V], the full well depth becomes:

0.600 [V] ∙ 1/1.502E-5 [e^-/(V∙pixel)] = 39,947 [e^-/pixel]

For comparison, Avante states the full well depth as 120,000 [e^-/pixel]. I’m off by a factor of 3.

Given an ADC with 16 bit resolution, the change in voltage per count on a given pixel is:
0.600/2^16 = 9.155E-6 [(V∙pixel)/count]

That leads me to a photon per count of:
1/1.502E-5 [e^-/(V∙pixel)]∙ 1/0.95 [photon/e^- ]∙ 9.155E-6 [(V∙pixel)/count]= 0.642 [photon/count]. That doesn’t make sense.
Again for comparison, Avante states the sensitivity as 60 [photon/count]. I’m off by two orders of magnitude.

There is something fundamental here that I don’t understand. Any guidance would be greatly appreciated and could help others attempting to analyze similar photon budgets.

UNITS: [ V/((W∙s)/m^2) ], [ V/((W\$\ast\$s)/m^2) ], [ e^- ], [ photons/count ], [ V/(lx∙s) ], [ V/(lx\$\ast\$s) ], [ V/lx\$\ast\$s ], [ lx ], [ lm/m^2 ], [ nm ], [ lm/W ], [ e^-/pixel ]

SCREENSHOTS:

CCD Chip

Compact CCD Spectrometer Summary Specs

Avantes Assessment of Detector Specs

EDITED: To improve readability and to include screenshots of highlights in certain links.


texts: Why gate drive transformer is not connected directly to the gates in this App Note?

texts:
Here’s a circuit from TI App Note SLUA323, which shows a synchronous rectification in a current doubler circuit.

U2 is a gate driver.  Transformer T2, which looks very much like a gate drive transformer, provides both signals and power to U2.  The output voltage is only +3.3V, which is a bit low for gate driving.  Transformer provides the gate drive IC with higher voltage.

Obviously, this circuit could be simplified if gates were driven directly by the secondary windings of T2.  What was the rationale behind adding U2?


texts: Measurement, Multi-pin voltage visualizer?

texts: Are there better&standard way to debug/inspect multiple pin voltages instead of a multmeter? It is rather inefficient.


texts: Help in understanding a circuit (Piezoelectric sensor)

texts:
This circuit is meant to produce logic level outputs to HIT1 and TRIG1 when an input in detected at X1.

I need to explain the operation of the circuit, calculate the unknown resistor values, explain their roles and determine if there are some components missing, however I'm struggling. Any help/hints would be appreciated in understanding how it works.

I know that OA1 is the Op-amp and CP1/2 are comparators, where the output of the comparator goes into a digital scoring meter, why are two outputs required however?

Just any help understanding would be appreciated, thanks in advance.


texts: Calculating charge given current and capacitance over time

texts:
I it possible to calculate the charge on a capacitor when only having the current, time and capacitance value?

I tried using this formula to first calculate the voltage and from there the charge. But in this formula I'm missing the initial voltage V0.
would the resistance formula be \$V = \dfrac{1}{C} \cdot \int_{} idt+v0\$?


texts:
I know the difference in series and parallel and 12 or 24 volts it's a simple concept.
   What i would like to know is, which gives more run time on their respective inverters or does 24 volt just reduce draw from batteries?
   I will be buying a 1200 watt inverter 12 or 24 and only using it for aprox. 900 watts for a few hours at a time.


texts: Connecting different batteries in parallel - how to calculate the voltage?

texts:
I have an exercise: I have two ideal battieries connected parallel:

simulate this circuit – Schematic created using CircuitLab

I calculated a resistance of the whole circut: 0.666 ohm.

But how can I calculate a voltage of the whole circut?


texts: Am I over-complicating this data acquisition design?

texts:
I'm working on a project that involves periodically reading 16x 0~5V analog voltages from identical FSR voltage divider circuits using an ADC. Each FSR is connected to a gain/LPF stage before being read by an ADC. Each FSR's signal conditioning circuit is identical.

Originally, I was going to use 4x LM324's for the gain and filter stages of all 16 signals (along with all of the passives needed for the feedback networks). Having 16 of everything (including passives) seemed unnecessarily redundant if all of the gain/filter circuits were the exact same, so I thought about using an analog mux to switch between each FSR's signal, and have the muxed signal fed into a single signal conditioning circuit and ADC.

My reasoning behind this: if I needed to modify the gain/filter circuit, I could simply update the components once, as opposed to updating 16x of everything.

Currently, I'm implementing this design using a PSoC 5 LP, since it has the analog mux / op amp / ADC all in one package:

I am not well-versed in designing for multi-channel data acquisition applications like this, and would like to hear if this seems like a good/bad design, or if you think there is a better (or more elegant) way of approaching this task.

EDIT (1): The datasheet for the specific PSoC 5 LP chip (CY8C5888LTI-LP097) is located here. By "FSR", I mean "force sensing resistor". The set of 16 ADC measurements are taken at approximately 200 Hz (i.e. all 16 measurements must be taken in less than 1/200th of a second). I am currently operating the Delta-Sigma ADC at a 12-bit resolution. The output of each FSR voltage divider ranges from 0V (approx. 0 force applied to the FSR) to ~5V (maximum force before FSR saturates).

EDIT (2): The signals from the FSR voltage divider circuits would be in the low end of acoustic frequencies (the FSR's are measuring an occupant's exerted forces/pressure on the surface of an office chair), from roughly 500 Hz to DC (0 Hz) frequencies. I don't intend to capture all of the frequency content of the signals - hence the lower sampling rate.

Also, here is an image of the voltage divider circuit for the force sensing resistors.


texts:
PCB has lipo battery input Vcc and GND. The motor connected to PCB will draw max 30A. While trying to allocate plane for Vcc and GND a question came to my mind as which one is more important for current draw.

I have inner 0.5oz layer and outer 1oz layer.

My questions are:

1)Should i allocate 1oz outer layer for Vcc and inner layer for GND or viceversa.

2)Or since there will be a return current are they both equally important for current handling (for example even if i allocate enough copper area for Vcc and poor area for GND will this be a problem due to return current).

3) If we draw 30A from Vcc, is the return current also 30A.


texts: stm32f401 usart: start bit detection sequence when oversampling by 8

texts:
I'm currently using usart on stm32f401. I'm wondering how the receiver detects start bit when oversampling by 8 is selected.
The reference manual (RM0368) states that the start bit detection sequnce is always the same despite the setting of OVER8.

2 explanations came up in my mind:
(1). If the start bit detection is exactly the same like what is shown in the image, and the sample clock frequency is stable, the received start bit will be 16 sample clock cycles meaning 2-bit long compared to other data bits in oversampling-by-8 configuration.
(2). Though oversampling by 8 is selected, when the internal circuitry enters "START_BIT_DET" state, the sample clock frequency will dynamically speed up to 2x, so the received start bit is still 1-bit long.
I've no idea how to explain this part of the manual.


texts: How can I make a font for graphical LCD?

texts:
Friends,

How can I make a font for graphical LCD ?
I saw some font library and loop ...but I don't know exactly how to use it ?

Anyone has experience and reference ?
I mean, similar to this function, I must try to display from character first before I display one word or one sentence,

Example of A in HEX :

uchar code AsciiLib[] = {
/* A */
    0x00,0x00,0x00,0x10,0x10,0x28,0x28,0x28,0x28,0x7C,0x44,0x44,0xEE,0x00,0x00,0x00,
}

I tried to create one function, please correct if it's not right :

#define uchar unsigned char
#define uint unsigned int

void DrawSingleAscii(uint x, uint y, uchar *pAscii, uint LineColor,uint FillColor, uchar Mod)
    {
        uchar i, j;
        uchar str;
        uint OffSet;

        OffSet = (*pAscii - 32)*16;

        for (i=0;i<16;i++)
        {
            Set_ramaddr(x,y+i);
            send_command(0x22);
            str = *(AsciiLib + OffSet + i);
            for (j=0;j<8;j++)
            {
                if ( str & (0x80>>j) )     //0x80>>j
                {
                    send_data((uint)(LineColor&0xffff));
                }
                else
                {
                    if (NORMAL == Mod)
                        send_data((uint)(FillColor&0xffff));
                    else
                    {
                        Set_ramaddr(x+j+1,y+i);
                        send_command(0x22);
                    }
                }
            }
        }
    }

Do you have example in function on how to display it ? I'm using C

Thanks a lot


texts: Are there any mature circuit board technologies that could withstand 300 °C?

texts: I need to reproduce a high density circuit pattern on something that can withstand temperatures around the 300 °C mark in order withstand molten plastic flowing through channels on its surface without de-laminating the tracks (the other side of the board would be ambient temperatures). Was reading something about single sided circuits directly on glass but I also would like to be able to include vias.


texts: How to dim my dc push button led switch that is too bright?

texts: Attached is a screenshot of my button and the dimmer I found, it’s getting a 12V source. I figured using wiring the pwm dimmer like the one shown will work. Please let me know your suggestions on if the dimmer will work and how to wire it inline with the switch to dim the led light.


texts: How to minimize hash noise in amplifier mounted near boost regulator

texts:
I've designed an audio low power (20W) guitar amplifier circuit whose pre-amp section has somewhat high input impedance, as is best for a magnetic guitar pickup. Since it operates from a battery supply, I'd hoped to employ a boost regulator so that the maximum output I have available before clipping would stay more constant as the battery voltage faded. My circuit also employs a simple compressor, which means there is more gain at lower volumes then at higher ones.

Unfortunately while everything was quiet and worked very well on the bench, I'm getting what I guess I'd call hashing noise as the components are brought closer together. The culprit is obviously the boost regulator, and the enclosure size makes it impossible to place that board more than about 6 inches away from the sensitive pre-amp circuits. Not surprisingly, the noise is worst when the amplifiers active treble control is maximized, and/or my compressor circuit is active. The boost regulator's oscillator operates at around 100Khz and of course generates additional harmonics, but I was surprised how much audible noise it added.

Which of the following do any of you think has the best chance of minimizing this problem (feel free to add more or tell me which ones likely won't help)

Shielding around the boost regulator (what material... grounded or floating
Adding more low value ceramic caps across the boost reg output
adding inductors to the boost reg output
Building a simple shield completely surrounding the amplifiers pre-amp electronics

At this point I'm strongly considering just ditching the boost regulator idea, if I can't drastically decrease this problem. FYI, the boost regulator is a fairly common one good for moderate power, Max6A 4.5-32V to 5-60V, often sold on ebay or ali express. You may recognize it from the picture...

As requested by Andy, I've added a picture of my basic wiring diagram, but of course its not truly "physical". Ignore the BTEST board, which is just a battery test board only active when a button is pushed. Note that my power amp board is separate from the pre-amp/control board, which is where also the PCB mount controls are soldered down.

Addendum: user96037 had the most helpful info here. This photo of the boost converter output is very telling...

There is 20mV (!!!) of noise at 176Khz here, much more if you count those spikes. The harmonic content is huge, so all my wires are behaving as antennas. It is obvious to me that if the amplitude can be cut and the waveform softened, I just may be able to salvage my use of this boost regulator. Already I've seen that adding a "random" pi-filter helps a LOT. (By random I mean my inductor was just 100 turns around a nail). I've ordered some better (toroidal) 100uH inductors and will try to come up with the best capacitors. Of course my next challenge will be keeping my inductor far enough away from the coil on the boost converter, and figuring out the highest value capacitors that still offer decent high frequency behavior.

Thanks again everyone... I'll update this thread with my progress for the benefit of anyone else dealing with this issue.


texts: Path of current and equivalent resistance

texts:
In this circuit, the current can flow from node 1 to node 2 through two different paths i.e either thorugh R2 or (R1+R4). Since the current selects the easier path I expect the current to flow from R2 only. But I often see the combination of resistors being reduced to single equivalent resistance. Is it because the parallel combination further reduces the resistance or anything else? I am sorry if the question is stupid.

simulate this circuit – Schematic created using CircuitLab


texts: Absolute address of a function in Microchip XC16

texts:
Device: dsPIC33FJ128GP802

I have some *.s files as follows

.global _D1
.section .speex, code
_D1:
.pword 0x66C821,  0x1B0090,  0xD96C36,  0x9B60B0,  0xDD4E36,  0xBF4E53
.pword 0xD1098B,  0x719BD9,  0x873989,  0x003B69,  0x279035,  0xED4244
.pword 0xE1403C,  0x54D439,  0x826550,  0xC59627,  0xDD0432,  0x88FA29

I have declared the same in a *.h

extern void D1(void);

Now I am passing the D1 to a table read function

nowPlaying.file1 = (unsigned long) D1;
function(nowPlaying.file1);

My problem is that, if the address of D1 is above 0X8000, the routine is not correct. I tried large and small code models, but the result is the same.
I think this is due to the 16 bit limitation of the pointers
Is there any method to access the absolute address of D1 directly from the code. May be something like built in function or macros.


texts: Receive serial data on multiple pins ATTINY85

texts:
I am working on a project in which multiple ATTINY's need to send numerical data between each other. In most cases the ATTINY will have to receive multiple streams of data on different pins. See the image below:

So in this case the ATTINY needs to receive data on the top right 3 pins at the same time. And needs to send data from the bottom pin to an other ATTINY.

I looked at doing this with the Software serial library but this doesn't support multiple pins and doesn't allow multiple pins to send and receive data at the same time.

So i heard that some sensors / modules have extra hardware to take care of the serial communication.

So my question is if it is possible to add this hardware to each pin so the chips can receive data on multiple pins at the same time. And what components should i use to accomplish this behaviour.

This is my first electronics project so please don't be to harsh. (I do have quite some coding experience).
If more information is required or if something is unclear let me know so I can clarify.

Thanks in advance!


texts: Relay switching a light causes a spike, making a raspberry pi halt

texts:
The problem in short:
I worry that switching lights is causing a spike. Occasionally a Raspberry Pi halts completely after a relay is switched.

The setup:

A Raspberry Pi 3 is connected to an Arduino Nano over Serial. The Raspberry gives the Arduino the command to switch a relay (when a PIR detects motion). This turns on 3 fluorescent tubes on 220v in series.

The TV that is connected to the HDMI port of the Raspi sometimes flickers when the lights get switched on. And every now and then (at least once a day) the Raspi just completely halts. No SSH/VNC possible, no HDMI video output. But still the red LED is on.

Why I assume the lights are the culprit:

Every time the Relay switches, the TV flickers. I think there might be a spike in the circuit but I'm not a professional. Also, the logs of the Raspi are completely clean. Which makes it likely there is no software problem here. I have a couple similar setups that work fine. The only difference being that they just switch 1 regular light bulb, rather than 3 fluorescent tubes.

The question:

Is it likely that the 3 lights draw so much power they disturb the TV and the Pi? If so, how can I prevent this from happening?


texts: Capacitors on DC power rails / voltage divider - analyzing a circuit

texts:
beginner here, please be nice :)

I'm interested in the following DI-style box for my guitar, which I'm going to build, and I'm working on analyzing it.
http://www.generalguitargadgets.com/pdf/ggg_ssim_m_sc.pdf

So far I've done reasonably well with figuring out the 4-stage op-amp filters. I'm considering filtering out the DC at the end (I think it's at ~4.5v?), and reducing the gain by modifying R2... but there are some basics that I am not sure on.

The top part of the schematic uses a voltage divider to power the op-amps, it seems so that it can amplify the AC signals from 0..9v, centred on ~4.5v.

C10/C11 seem to be part of low-pass filters to strip AC from the power lines

why would we bother doing this if we assume the power supply is clean, or use a battery?
how can C10 filter the +9v rail without a resistor? wouldn't the 9v just snap to the power source and bypass the capacitor?
My calculations put the C11/R13 low-pass filter very low, at 1/3 hz. I guess that's basically strict DC?
assuming the op-amps take their power from the power rails, wouldn't this modify the voltage divider, making the DC offset change dynamically based on power consumption?

I assume these are basic / beginner questions for AC circuits, so I hope they're easy to answer. I appreciate all the help in advance.


texts: Calculating Short Circuit Current when Nortonizing a Circuit

texts:
My objective is to find v (voltage drop across 8 ohm) in the below circuit. I was able to thevenize the circuit successfully (V thevenin = 12 V and R thevenin = -2 ohm) and find v. But I find it difficult to apply Norton's Theorem in the below circuit.

simulate this circuit – Schematic created using CircuitLab

The Norton equivalent resistance is easy to find (-2 ohm). To find the short circuit current, I shorted the 8 ohm resistor. This will also short the 4A current source and will hence become redundant (No interaction with left side of circuit). This reduces to the following circuit:

simulate this circuit

From the above circuit I wrote the following:

\$i_{N}=-(10-i)=i-10\$

\$\Longrightarrow i=10+i_{N}\$

Applying KVL to the mesh:

\$-2i+4i=0\$

\$i=0\$

\$\Longrightarrow i_{N}=-10 A\$

This is not the same as:

\$\dfrac{V_{th}}{R_{th}}=-\dfrac{6}{7}A\$

What have I done wrong? Have I overlooked something?

Edit:

I will show here how I calculated R thevenin. I first detached the 8 ohm resistor from the circuit and nullified all independent sources.
Since the circuit has dependent sources, I attach a 1 V voltage source across the terminals AB.

simulate this circuit

\$R_{Th}\$ then becomes \$\dfrac{1}{i_{0}}\$. The idea is to find \$i_{0}\$ which is the same as \$i\$.

You can read more here:
https://www.allaboutcircuits.com/technical-articles/thevenin-theorem-dependent-source-circuits/


texts: Is it safe to run a 7.5 volt electronic on a slightly higher or lower power amount?

texts: I have a CASIO SA-75 that has corroded battery terminals. I have tried finding a power supply for it. It is rated for 7.5 volts, but all of the power supplies I found were 7 to 8 volts. Can I run the CASIO on these power supplies without worrying that it will die?


texts: External clocking of MSP430 with variable duty cycle clock

texts:
I'm going to clock an MSP430FR5969 using a PCF2127 RTC. The PCF2127 can output 32.768kHz at a duty cycle between 40%-60% and 16.384kHz, 8.192kHz, etc at exactly 50%. I will use the MSP's DCO system to generate an 8Mhz internal clock from this LF input.

Will the variable duty cycle @ 32.768kHz be a problem or should I change the RTC output to 16.384kHz to guarantee a 50% duty cycle?


texts: Is there any (open) powerpoint library of components that could be used to build presentations with electrical/electronics circuit ?


texts: BIL, Dielectric Breakdown, Shrink Wrap, and Safety. Is there a resource for this information?

texts:
I am currently working with a system that produces high voltage transients for system testing, and have some cables that need to be made/modified to work with some new equipment.

The operating voltage through these cables is (relatively) quite low, with a supply limit of 300 VAC RMS, at 16.4 A absolute max from the supply. The system is not typically required to operate near those limits, but should be capable, if required.

All of the connectors are Class III (1000V) or Class IV rated, which includes a surge rating that is more than sufficient. The wire is 10 AWG with heavy silicone insulation, sourced from extra cables that were provided by the system manufacturer.

What I would like to be able to do, is manufacture 'new' cables, by connecting new terminals/connectors (solder) and cover them with shrink wrap to prevent any external contact with the conductive elements while they are in use.

The problem I am running into, is how to assess the insulation requirements of the shrink wrap, for times when surge testing is being performed. We regularly produce 1.2/50 microsecond and 10/700 microsecond pulses, up to 6kV, that will run through the new cables. In a short circuit current condition, this can produce 1kA for the same duration. At maximum repetition, these pulses are once every 10 seconds.

The most information that I can find about many products is the dielectric breakdown (in Volts per unit thickness) and by that metric, many of the heavier duty products would be more than adequate.

My question is, can that number (dielectric breakdown) be used to reliably assess safe insulation levels for such high energy pulses, assuming that the pulse voltage is lower than the breakdown?

Or: Is there a way to assess Basic Insulation Level from information that is readily available?

I have tried contacting several manufacturers directly, but have either been ignored, or have been directed to products that are rated for 6kV+ of constant voltage on bus bars (and were MUCH too big for wires that are only 10 AWG to be protected).


texts: How much current can you pull safely off a standard AAA battery?

texts:
This might be a stupid question. But how much current can you safely draw from a AAA battery.

I am currently powering my project from a worktop power supply and it draws at 5V 0.45A during normal operations and peaks to 0.7A. Now I need to make it portable and looking for the right battery. I need to keep my project as compact and light weight as possible. I was thinking of using four AAA batteries or suitable Li-ions to power it on the go. The max duration I expect is 1hr but I will be satisfied with 45 mins.

If you have any other suggestion of powering the project please help me out.


texts: Is the impulse response of a real system is always a real function?

texts: As stated in the title, is the impulse response of a real system is always a real function? Can it ever be complex/analytic, etc.? I'm more interested in terms of radar systems. Any info would be helpful.


texts: Comparison of data transfer between different bandwidths

texts:
Which of the following can transfer more data [bps]

10Hz bandwidth over 2s
20Hz bandwidth over 1s

It looks like its the same bps but I'm not sure.


texts:
I appreciate that different applications have different criteria, but could someone give a ball park figure of how much attenuation is needed for an anti aliasing filter at the Nyquist frequency to prevent aliasing?

For example I'm building a filter for the input of my PIC which samples at 10KHz and therefore the Nyquist frequency is 5KHz. I'm only interested at parts of the signal below 3KHz, so I have some leeway in my design as to whether I choose a second order/third order low pass filter, but I don't know which to design because I don't know how much attenuation at 5KHz would be sufficient?


texts: How do I convert ADC single-ended output back to voltage (ADS1115)?

texts:
I am evaluating some ADCs for my project and am trying to understand the operation of Adafruit's ADS1115 16 bit ADC (https://learn.adafruit.com/adafruit-4-channel-adc-breakouts/downloads) in single-ended mode. The ADS1115 ADC is from Texas Instruments and the datasheet can be found at https://cdn-shop.adafruit.com/datasheets/ads1115.pdf.
The datasheet says the fullscale input voltage is +/- 4.096 V - I believe that is the internal voltage reference - please correct me if that's wrong!
My confusion comes from the Adafruit documentation saying that "Single ended inputs can, by definition, only measure positive voltages. Without the sign bit, you only get an effective 15 bit resolution."
I thought that to convert my ADC bits back to Volts I need to take the output bits and multiply by the number of levels (e.g. 65536 for a 16 bit ADC) divided by Vref. So a Vref of 4.096 would give 6.25e-05 V/bit at 16 bit resolution but 1.25e-04 V/bit at 15 bit resolution.
I am guessing that what they are saying is that the 16 bit resolution is for differential input,which over the maximum voltage range of +/- 4.096 V is 65536/(2*4.096) = 1.25e-04 V/bit. That is equivalent to 15 bit resolution for single-ended measurement. This is different from the documentation of, say, the ADC in the Atmel SAMD-21 chip where you still get 16 bit resolution for single-ended measurement if I am reading that correctly.
Cutting through all of this, my question boils down to if it is correct to use 1.25e-04 V/bit for single-ended measurements from the ADS1115?


texts: Charging a capacitor and then introducing a dielectric

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Suppose I have a capacitor and I charge it up using a circuit with a battery to the maximum amount of charge that it could hold.
Now, I unplug the wires and insert a dielectric inside.
I know that electrostatic energy between the capacitor plates changes when I do this, however, where does this energy go/come from? Very specifically how does insertion of dieletric change the energy? Is there any intuition behind this?
Secondly, how would the charges on the capacitor change at the point where I remove the battery and also the point where I insert the dielectric?
Finally how would I find the maximum amount of charge that I can allocate onto the capacitor?
The kind of answer I am looking for:
One which explains using electronic demonstration motivated by some mathematically derived theoretical results
Further, I'd also like to know what would be the effect of 'induced charges' on these processes and if we can ignore them or not. How does charge conservation explain induced charges?


texts: High step up DC-DC converter switch mode power supply

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I tried to design DC-DC high step up isolated single switch converter and simulate it in Proteus 8 professional, that design have a gain reached to 20 if that possible? and I confused by one thing, I am really new in switch mode power supply especially in isolated ones, but I am notes that the transformers designed as step down anyway if the converter was buck or boost, is that right or not?

simulate this circuit – Schematic created using CircuitLab

in the above circuit diagram is the proposed topology, is this considered isolated SMPS or not?
I tried to simulate it but I can not get the desired gain as 20.
please, I tried it a few weeks ago but I can not get the desired results.


texts: What kind of circular 16 pin connector is this?

texts: This is a connector on some device.  I need to build an adapter which goes between the shown parts.  Is this some kind of "standard" connector?  I see 16 pins. The device is from the US.  The connection is digital/serial at 3.3V level.


texts: How to integrate current signal to be able to measure it with 50 ohm input impedance of ADC

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Preliminaries
I am using a photomultiplier tube (PMT) in order to amplify scintillator's light signals. Some of the studied scintillators have long decay time and poor light yield. That makes these signals difficult to use as a trigger on an oscilloscope/ADC (because of the noise that has similar amplitude). This is how they look like on 50 Ohm load of the oscilloscope:

In case of the oscilloscope as a measuring tool I solved this problem using the RC-integrator. NOTE: PMT is a current source:

simulate this circuit – Schematic created using CircuitLab
This gives me time constant about 800ns which is enough to discriminate signal pulse shapes. This is how they look like on 1MOhm load of the oscilloscope:

Requirements
I need to be able to preserve information about the scintillation curve. E.g. using the above-mentioned RC-integrator I know the response function:

So making an assumption about the exact form of  I can restore its parameters later.
Problem
However, I cannot use the same approach with ADC as a measuring tool because unlike the oscilloscope it doesn't provide an ability to change the input impedance. Its input impedance is 50 Ohm. For example, adding a resistor in series with the input of ADC obviously doesn't fit because of a voltage division. What should I do in this case? I thought if I could change the input impedance effectively and then use the previous solution.
EDIT (The device list)

PMT : Hamamatsu R1847S @ 1500V
Oscilloscope : OWON TDS8204, Z_in either 50 Ohm or 1M Ohm
ADC : CAEN N6720A, Z_in = 50 Ohm