texts: Boost Converter/ Inverting Converter Noise Measurement

texts:
I built a boost/inverting converter using TPS65130. The output voltage is +15V and - 15V. Below is a picture of the schematics:

I know the schematics shows a zener diode symbol, but that's just a mistake. I'm using a schottky diode. Also, the base of U37 is not connected because I have a zero ohm resistor across R50. U41 is an LT3094 and U42 is an LT3045, they are both linear regulators used to filter noise.
What I'm trying to do is to measure the noise of the power supply. Here is the procedure that I followed to measure the noise of this power supply:

used a 1:1 probe that has a max bandwidth of 35Mhz.
used a bandwidth limit of 20Mhz on the oscilloscope.
used a ground spring instead of the long ground lead. I also made sure there is nothing else connected to the oscilloscope picking up common mode noise.
I measured directly at the output capacitor C152 for the boost and c179 for the inverting converter.
the load current is 80mA.
AC coupling.

The problem is I noticed some weird overshoot and undershoot. The first picture shows what I see when I measure directly across C152 which is the positive supply:

The next picture is what I see when I measure across C150 which is after the linear regulator:

The Next picture is what I see when I measure across C179 which is the negative supply:

The final one is if I measure across C1 Which is after the linear regulator:

I have checked everything including the inductor and output capacitors. Checked things like saturation current, rating current, etc. These waveforms repeat and when I measure the frequency between two repeating waveforms, I get 6Hz. This is the same for both the positive and negative supplies.
Any Idea on what this could be?
Edit: I noticed that the problem disappear if I lower the input voltage to 4V. Not sure why does it work with 4v better than 5V.


texts: Why does digital equipment have more latency than analogue?

texts: Is the explanation that the digital equipment takes longer to propagate? For instance, a software synthesis is very slow compared to a hardware synthesis.


texts: LMR10510 - Simple switcher "breakoutboard" output measures 0V

texts:
I have a problem concerning this Simple Switcher found here. I used the design example 3 for the LMR10510Y found on page 17 of the datasheet, however measuring the output pins of the switcher returns 0V on the Feedback and SW Pin. VIN receives 5V and EN is around 2.0XV. Here is a picture of my schematics and the board layout (I considered the layout considerations found in the datasheet):

Any Ideas what went wrong? If the question is too broad please ask!


texts: In the below image for Amphenol GSB343K33HR, do the 4 rectangular pads in the center of the image signify Shield connections?


texts:
I'm trying to learning boolean algebra.
One of de morgan's law is not understood.
how does A'B'C' convert to A'+B'+C'?

As I know,
1. (A'B')' = A+B
2. (AB)'=A'+B'
3. (A+B)'=A'B'
I think it should be (A+B+C)'.

Is this same between A'+B'+C' and (A+B+C)' or A'B'C' and (ABC)'?

http://www.indiabix.com/digital-electronics/boolean-algebra-and-logic-simplification/discussion-138


texts: Convention to label components in a circuit

texts:
Given an un-labeled schematic like the below, is there a convention on how to label the various components?

For example, would the 'top-left' resistor be R1? Would the one to the right of it be R2, or the one branching downward from it, etc. Are there conventions for this, or it just comes up to 'label it however you want' ?


texts: Best way to do sync separation without an LM1881 or equivalent

texts:
I have a PAL or NTSC video signal and I want to extract the CSYNC information. Preferably, I would like to avoid using an LM1881, because I am short on space and I'm optimising for cost.  Also, the LM1881 is limited to an operating range of 0°C to +70°C and I want a full industrial range of -40°C to +85°C.

So I set up a little divider network like this:

3.3V --------------+
                   |
                   /
                   \ 4.7k
                   /
       4.7u   1k   |
Inp  --| |--/\/\/\-+--- to PIC comparator
                   |
                   /
                   \ 4.7k
                   /
              1k   |
                  ---
                   -

This produces a signal with ranging from 1.27V to 1.5V, but the signal moves up and down when the brightness in the scene changes! I think this is happening because the DC offset is changing.

Any idea on how to eliminate this offset? I guess I could add some other components, but I'd rather not - I'm trying to keep this as simple as possible.


texts: current analysis with pre-carried current in the inductor .- confused

texts: The direction of the reference i(t) current is certain. When we add the pre-existing currents, it will be -12 amperes, thats okay. But why did we multiply it by - (minus) when we integrating the expression Voltage and multiply it by inductance (I marked it with a yellow marker)?


texts: I'm following this tutorial to make my own recorder PIC18 (http://rengenharia.com.br/?p=401), but I have a problem, I do not have the component "X1" (DB9 female connector for PCB). Anyone have any suggestions to replace/manufacture this component. And I still have another problem, my laptop does not have serial port only USB. Can I use USB instead of serial? I appreciate the response.


texts: DC to LIPO charging module reverse Feedback

texts:
I want to be able to use DC 12v to power my circuit but also have ability to have it powered by a battery.
The thought I have is:
* A on/off switch allows battery output to be switched on/off while wallwart 12v dc charges the battery and also provides the sufficient voltage to my circuit.
Using 1N4148 on batt output and on the 12v output (after the LM7805 Vin pin) to prevent from feedback.
* Using a tiny capacitor 2.2nf to take care of the ripple / noise from the switching convertor (MT3608)

I have few doubts / questions

1) In the circuit I am sharing ground everywhere. Is this safe or good practice

2) Will +ve output from the DC boost converter (MT3608) make a feedback to LM7805 and create problems ?

Please excuse my little to none know how on electronics. I am trying to learn while building stuff.

Please excuse me if this is re-post. I tried to search the forum could not find something similar. Please forgive if I have not earched well enough and kindly direct me to the right thread.


texts: Atmel SAM E70 (ATSAME70Q21, Cortex-M7) battery backup

texts:
I'm building a USB-powered demo board with the Atmel SAM E70 controller, and a single hurdle I'm facing is the battery-powered operation. I intend to use a simple 3V coin cell battery as a backup power source, and want to preserve MCU's current date/time in a low-power mode.

I have a minor STM microcontroller background and kinda expected Atmel MCU to have similar capabilities, but E70 (and the whole line of Cortex-M7-based Atmel MCUs, it seems) lacks the VBAT input. E70 datasheet has a separate section (22.4.4 - "Using Backup Batteries/Backup Supply") on the topic, but it doesn't provide any ready answers - only a sketchy schematic and some power sequencing advice.

E70 has a sister chip - the V71, and I've found that V71's demo board from Atmel ("V71 Xplained Ultra") actually does provide a detailed schematic, which is far from being easy & compact:

It seems that Atmel expects system engineers to build a backup power system of their own; it's a bit of a letdown, as STM F4/F7 line has an embedded backup powering scheme.

Thus, 2 questions:

Is there any easier (than building a scheme with an opamp and 2 additional ICs) way or a tried-and-tested schematic to provide a backup battery power for Atmel S70/E70/V70?

Note: I was advised to use a separate RTC IC (like STM M41T62LC6F), but don't feel comfortable with adding an additional IC to the board.
(in case any Atmel engineer happens to visit this question) What was the reasoning behind leaving out the VBAT/low-power controller out of the MCU?


texts: STM32 HAL_PCD_EP_Transmit work only once

texts:
I'm developing a USB composite device with the Nucleo-F446ZE.
I'm adding a Virtual com port and I have some trouble to send back data.
I receive everything from the computer but when I try to send back something it work only once. Then the EP->xfer_count is still at zero and HAL status is always 0.

//usbd_conf.c

HAL_PCDEx_SetRxFiFo(&hpcd, 0x40);
HAL_PCDEx_SetTxFiFo(&hpcd, 0, 0x20);
HAL_PCDEx_SetTxFiFo(&hpcd, 1, 0x20);
HAL_PCDEx_SetTxFiFo(&hpcd, 2, 0x10);
HAL_PCDEx_SetTxFiFo(&hpcd, 3, 0x20);
HAL_PCDEx_SetTxFiFo(&hpcd, 4, 0x10);
HAL_PCDEx_SetTxFiFo(&hpcd, 5, 0x20);

//init

USBD_LL_OpenEP(pdev,
             CDC_IN_EP, //0x85
             USBD_EP_TYPE_BULK,
             CDC_DATA_FS_MAX_PACKET_SIZE); //64

USBD_LL_OpenEP(pdev,
             CDC_OUT_EP, //0x03
             USBD_EP_TYPE_BULK,
             CDC_DATA_FS_MAX_PACKET_SIZE); //64

//The receive/send back function

dataLen = USBD_GetRxCount (pdev, epnum);
Hstatus = HAL_PCD_EP_Transmit(pdev->pData, CDC_IN_EP, VCP_recv, dataLen);
HAL_PCD_EP_Receive (pdev->pData,
    CDC_OUT_EP,
    VCP_recv,
    CCID_BULK_EPOUT_SIZE);


texts:
I built a circuit for a simple amplifier that can use both bluetooth or a 3.5mm connector. The problem is that I am getting noise when I use the bluetooth module. There is no noise when I use the 3.5mm connector or when I power the bluetooth module from a second power supply. This leads me to  believe that there is something with ground loop isolation, which is why I put a transformer in the circuit. This didn't work, and I do not understand what to do to fix it.

Ignore the fact that I went from stereo to mono and then use the rest of the circuit as though it were stereo. That is because I have only one transformer.


texts: For a S-R latch made of NAND gates, what happens when the latch is just powered and both the inputs of the latch are provided with logic level 1 simultaneously. What output do we get? Do the outputs remain constant or keep on changing?


texts: How to make a phone think it has a battery on it and run it from a charger

texts: Im trying to run  a samsung galaxy s7 edge without a battery on it but it just turn on shows a logo and then turns off again i think it knows that there is not a battery inside so if anyone knows what to connect to make it think it has one or what i can do


texts:
It's been a very long time since I took intro level EE courses. I'm working on a hobby project and as a refresher I figured I would simulate a CMOS inverter. For the life of me I can't figure out why the simulation doesn't produce the expected results.

I believe I've faithfully reproduced the circuit from Wikipedia. I've wired it so the drains of the two MOSFETs are tied together. The source of the P-MOSFET is tied to the positive voltage. The source of the N-MOSFET is tied to ground.

I ran a simulation that stepped the gate voltage from 0V DC to 1.5V DC. The spec sheet for the MOSFETs say that their threshold voltage is in the range of 0.3V DC to 0.8V DC. The simulation showed pretty much no change in the output voltage. I re-ran the simulation from 0V DC to 12V DC and it produced the graph below.

Why is it that the output voltage doesn't change rapidly in the range of the threshold voltage of the MOSFETs? I was expecting it to drop from 12V DC to 0V DC very rapidly after the gate voltage exceeded 0.3V DC.

The Circuit

Vout, Vmax as a Function of Vgate Over the Range 0V DC to 12V DC

Vmax is the green line

Vout is the black line

Vgate is the blue line


texts:
I need help solving the circuit above.
I don't understand how to analyse the op amp using the small signal model in order
to calculate the Vout/V3, the input resistance (Rin) and output resistance (Rout).

Any help would be appreciated

Thanks


texts: Trans-impedance Amplifer with a Fully-Differential Amplifier

texts:
I'm designing a trans-impedance amplifier (TIA) for a fairly fast Avalanche Photodiode (APD), to amplify pulses of 1mA that last few nanosecond. I found a solution that have just enough bandwidth with a single-output op-amp, but I want the output signal to be differential, and I haven't found any integrated TIA that meet my specifications.

I looked at several Fully Differential Amplifier (FDA), like the LMH5401, and designed a circuit close to that one:

simulate this circuit – Schematic created using CircuitLab

I could not find any example of a similar circuit. While I can pick \$Z_{f+}\$ and \$Z_{f-}\$ to achieve the performances I want, I'm not sure how I should check my design.

How can I check that the circuit is properly balanced?
Does \$Z_{f+}\$ and \$Z_{f-}\$ have to be equal?
Is there any show stoppers that a SPICE simulation won't catch?


texts:
I'm attempting to make a quadcopter using an Arduino board (Blend Micro). I've wired everything up as such:  When I run the following code just to test if everything is working, the motors do not spin at the same rpm:

void setup(){
  pinMode(9, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);

  analogWrite(9, 100);
  analogWrite(5, 100);
  analogWrite(10, 100);
  analogWrite(11, 100);
}

M1 will spin  as expected, M2 and M3 will spin very slowly, and M4 will not spin at all.

The pins (D5, D9, D10, D11) on the Blend Micro supply 3.3V, 20mA max.

I have checked the wiring many times and there are no shorts/everything seems ok.

Extra:

The motors are rated at ~3.7v max (therefore I planned to not exceed 70% for PWM)
At 3.3v, the motors draw ~1A each (so I assume I need to change the 2N2222 transistors)


texts:
Recently I had an explosion on my desk. A 220uF 25V electrolytic capacitor just blown up shortly after attaching a load.

The high-level connection was:
Phocos CA08 (solar charger controller) -> 12V-3.8V step-down -> uBlox Leon GSM modem.

Because the variable load generated by the GSM modem was causing the charger controller errors (it indicated an overload and cut off the voltage at the output socket) I put a 220uF 25V electrolytic capacitor on its exit and it worked for a week or so with no issues, also no overload indications were occurring anymore. The connection was not firm, it was just attached into the contacts of controller's output. There was an external power supply attached to the the solar cell so that to charge the lead-acid battery. The explosion occurred after ~5 seconds since attaching the K1 to the charger controller's output.

The schematic of a power supply for the GSM modem is the following:

The modem itself can generate a significant load when registering to the network (right after power up):

It came to me as a surprise that the capacitor like this exploded this way, especially when it is not the only capacitor on the path between the supply and modem, there are plenty of them.

Now I wonder what happened and what might have caused the explosion of this type. I did not change the polarization of the capacitor, I'd bet that its leads did not met each other. Do you have any ideas?


texts:
I am working on a very spotty motor failure (I am not the designer).  We have a wound armature which is switched by power MOSFETs.  These are driven by a FET totem pole type FET driver.  When the driver is off therefore, the gate of the power FET is floating.  Yeah, I know.  Bad design choice.  I'm just cleaning up the mess.

There is a triac and drive circuit controlled by a micro output on the stator side of the motor.  When you plug the motor in, the drive line is floating since the micro port is tristated until boot is complete.  Since this port line is going into an AND gate and floating, you end up with about 5 cycles of AC on it of sufficient amplitude to fire the gate and this the triac.  This puts about 3-5 half cycles of the line on the stator, with peaks of up to 100A depending on source impedance.  Yup.  Another design error - it should have been pulled down.

Problem - this does not happen often, nor does the power MOSFET failure.  Out of hundreds of motors, we have had three fail with power FETs shorted drain and gate to source.  Question - I am trying to decide if this series of current spikes (which do induce voltage onto the armature - and the turns ratio is 1:1) is a likely suspect, given the poorly designed power MOSFET circuit.  The MOSFETs are right across the armature winding.  When the motor fails, it does not fail during run.  It seems to fail as soon as you plug it in.  My evidence is all circumstantial - I have so far been unable to force a failure.  But the massive spike at plugin, the rarity of the failure, and the difficulty of duplicating it seem to point at this.  If I'm going down the wrong path, I need to know and know why.  This seems like it may damage the FET, but I'm looking for path to failure here that makes sense.

At the moment I am cyling several motors, using a PLC to keep an eye on them.  The plan is to cycle until failure, apply design corrections and run again.  Unless I get a flash of genius.


texts:
In my PCB, there are two GND polygons (1 & 2) which are connected to the same GND plane. The only way I was able to connect them was through vias as shown below:

I realized that two current paths current could happen (the desired path and undesired path). However after looking at it further, I think that the undesired path is not likely because electrons will be flowing from GND polygon 2 to GND polygon 1 through the via trace. These flowing electrons will repel the electrons flowing in GND polygon 1, leading me to believe that this layout is ok. Is this the case, or should I be concerned about the undesired path/ other issues I may be overlooking?


texts: What is actual horsepower of this single phase ac motor

texts:
I'm looking for a 1/6 HP motor for my lathe and found a motor with specs I like except for low 1/60HP. So I found many online horsepower calculators and entered the motor plate info:115V, 1.1A, 60Hz, 1568 rpm and results were .137 to .166697 horsepower. That is a factor of 10x higher than plate marking. I tried this with other similar, low horsepower, motor specs and got similarly higher horsepower results. Why is there such a large difference between plate marking and calculators results? Or am I not understanding something?
I also used amps, PF, voltage and efficiency calculators entering plate markings. I then entered the lowest values of .8 PF and 65% efficiency values and got approx 1/10 hp results. That is quite a bit larger than 1/60 hp.
Just added photo.
Thanks


texts: LTspice inverting op amp circuit does not function at all like expected

texts: I am new to LTspice and as an exercise I am building an inverting op amp. I have built this same circuit on a bread board and in every circuit and gotten the results I expected. However, in LTspice the the output voltage is always at ~1.5V no matter the resistance ratio and for most input voltages. Does anybody have an idea as to why this is? The green line is the input voltage before R1 and the blue line is the output voltage of the op amp.


texts: This is a signal diagram of a transmitter. I don't know the mean of parts are shown in the image. What kind of signals are they? What are their meanings?


texts: Motorised blind controller schematic - do I need to protect ICs with resistors?

texts:
I am making a simple motorised blind controller, which I want to have a "safety cut out" when it gets to its fully closed/fully open state. (So the user doesn't strain the motor keeping their finger on the button when it is open/closed.)

I'm a bit of a noob, but it seemed fairly straightforward in terms of logic.

Basically there will be a reflective IR sensor at the top, and at the bottom (level with the fully closed position of the blind). The logic is that when the user presses the up button, if the top sensor is high (i.e. the blind is in front of it) the motor will run until either they let go of the button or the sensor goes low (because the blind has passed it).

Similarly, if they press the down button, the motor will run in the opposite direction (controlled by an L293D chip) if the bottom sensor is low (i.e. not covered by the blind). Again this continues until the sensor goes low (blind has reached the bottom) or they let go of the button.

I've drawn up a schematic, and I think the logic is right, but I wanted to check if I need to protect the chips with resistors. I'll power it with a 5V 700mA mobile phone charger for the 5V supply, and I'll also need a separate 12V supply for the motor. (Will join the grounds from both).

Is there anything else I am missing, or any noob gotchas I need to be aware of?

Also - if I have made any howlers on the schematic layout / broken any major conventions, please feel free to put me straight! (Can't figure out how to attach a clearer version as it looks like it has been scaled down to fit.)


texts:
I have a Arduino Leonardo board. and i get an error : avrdude: stk500_getsync(): not in sync:  resp: resp=0X54

I have downloaded the Arduino environment from here. I am on my Mac.

I selected the Arduino Board as Arduino UNO, and the serial Port as /dev/tty.usbmodemfd121 and when i click on the upload button i get the error message avrdude: stk500_getsync(): not in sync:  resp: resp=0X54.

When I click on the reset button, and click on Upload, I get a popup window that says Serial port /dev/tty.usbmodemfd121 not found. Retry the upload with another serial port.

and in the list of serial ports, i have

/dev/tty.Bluetooth-Modem
/dev/cu.Bluetooth-modem
/dev/tty.iphone-wirelessiAP
/dev/cu.iphone-wirelessiAP
/dev/tty.Bluetooth-PDA-Sync
/dev/cu.Bluetooth-PDA-Sync

What should i do to run my Hello World code ?

UPDATE

Binary sketch size: 4,858 bytes (of a 28,672 byte maximum)
Found programmer: Id = "B¯˜"; type =
 Software Version =
avrdude: error: buffered memory access not supported. Maybe it isn't a butterfly/AVR109 but a AVR910 device?


texts:
I am reading the datasheet for a TB6612FNG dual H-bridge and see the term "Short Brake". I would like to stop a single motor for an extended period of time. Can (or should) I do this with the short-break function?

What does the term "Short Brake" mean? Is it short, like a short circuit? Or short like momentary?


texts: Li-Ion Protection IC Always in Overcurrent Detect Mode

texts:
I am seeing an issue with AP9211SA-AF-HAC7 Battery management system.

The battery protection circuit, designed as per the schematic attached (the same as the reference design in the data sheet(https://www.diodes.com/assets/Datasheets/AP9211.pdf)), continuously enters over current mode with any load that draws more than 1-2mA attached.

If the circuit is powered, then the load attached after, everything works as expected, it will happily allow up to 1A of current draw the the Voltage of the battery.

As this is an auto-wake-up version of the chip, it comes out of under voltage lockout fine, as long as there is no load attached, as soon as there is a load applied, this is not the case and the chip returns to overcurrent protection mode.

I am unsure of how exactly the Vm pin monitors the current and am wondering if this could be the cause? but it is the same value as stated in the datasheet so I'm really not sure what is wrong here.

Any explanation/help would be greatly appreciated.

NOTE:

I have tested multiple chips, also multiple versions of the same
   chip
 - AP9211SA-AF-HAC7
 - AP9211SA-AJ-HAC7
 - AP9211SA-AA-HAC7
 - AP9211SA-AB-HAC7

I have also tested my circuitry using a bread-boarded version to rule out any issues with my PCB layout.


texts: Failures on underside layers of a chip in IGBT power modules

texts:
Does somebody know how I can detect a layer of IGBT modules in which a thermal failure, e.g., voids, cracks, delaminations of solder joints, has taken place?
We know there is fatigue in both solder joints of wire-bond IGBT power modules, one joint is between chip and DBC and another joint is between DBC and baseplate. When operating IGBT module, how can I find which joint is degraded? Is there a specific technique to detect it in practice?


texts: Parasitic source and gate inductance of SiC MOSFETs

texts:
I have a question about a tutorial video from PSIM: https://www.youtube.com/watch?v=iATO3mUKBPc

In this video, a MOSFET circuit is created using LTSpice .lib files from Cree. The parasitic drain and source inductance is indicated in the video with a parallel resistor. This resistance value and also the parasitic inductance can be taken from the .lib file. For the MOSFET used in the video the following is given in the .lib file: Ls = 9n, R_Ls = 10, Rg = 11.4, Lg = 15n, R_Lg = 10, Ld = 6n, R_Ld = 10.

My question is why this resistance value of 10 ohms corresponds to a parallel resistance of the inductance. I always thought that the parasitic inductance and the resistance are present due to the pins of the package (like TO-247). However, to my knowledge, such pins would present a series connection of parasitic inductance and parasitic resistance. Can someone please explain to me why a parallel connection is assumed?

Thank you in advance!


texts: Differential pairs; length matching between pairs

texts:
I'm currently busy routing a high speed design containing MIPI signals @ 2,5Gbit / lane to a connector on an 8 layer board. As MIPI also contains a clock pair, it is advisable to match the length between pairs as best as possible.

I've come pretty far so far with matching <0,05mm, but I'm wondering what is the best option to extend the length of a trace, see below picture:

Some information:
Blue = layer 1
Green = layer 3
Purple = layer 6

Layer 2 and 7 are ground layers

Option 1 is extending the traces on the inner layer and running them back on top to the connector. To me, this seems like an excellent option, as it gives me maximum spacing towards other traces. However, I'm wondering how much of an influence the traces running back towards the connector exactly on top of the layer 3 traces has. It is a differential pair, and there is a ground/reference layer in between, so I would think this would allow only minimal crosstalk or other effects.

Option 2 is the traditional serpentine tracing. This would be my least preferred option, but I don't have much choice because I can't extend the traces behind the connector.

However, if option 2 is preferred for whatever reason, I could change the option 1 by retracting the traces back towards the connector as much as possible, and add serpentine tracing on layer 3.

So my question, which of these 2 options would give best signal integrity and/or EMI compatibility?


texts:
I want to connect different LEDs that have these parameters (the LEDs I am using are just generic LEDs I got from ebay.):

Led 1: 6.4V - 7.2V  @ 0.7A

Led 2: 2.9V - 5.6V @ 1.9A

Led 3: 8V - 12V @ 3.4A

Led 4: 50V - 56V @ 2.8A

Recently I recovered a computer PSU that has an output of 12V, 16A.

Assume that the PSU is centrally located while each LED is in a different room (kind of a wheel).

If I connect the exit of the PSU with this driver and for LED 1, this  driver for LED 2, will it work? Or i am going to create a new smoke project?

Do the step down/step up converters be able to limit the current on the output or it will burn the LEDs?


texts:
I am an embedded enthusiast and very much into embedded C and firmware development.  I love to interface different sensors and modules to MCU by creating my own libraries from scratch.
Now for understanding signals and protocols used by sensors and modules like UART, SPI(High-speed ones too), I2C, timers, PWM waves(of order ns, us, ms), one wire communication, ADC, CSI, RS232, IR receiver protocols, RF433 module of and many such protocols used in different MCU to interface different sensors and modules (like using STM32, NRF5.)
So which equipment I should go for,  a logic analyser or oscilloscope?
My personal thought is to go with a logic analyser, as my main task is with handling MCU protocols and almost all of them work on digital signals only, that is what logic analyser is mainly for I guess.
But I am confused as to which logic analyser will be best for my needs.
Still on the choice between logic analyser and oscilloscope, experts advice from you all?
P.S. I am loking for cheap solution, not too expensive.)


texts: How does Frequency-division multiplexing deals with overlaps?

texts:
As I understand it, FDM uses separate frequency for each channel, thus A will transmit data, for instance, every two seconds and B every three seconds.

But, what will be delivered on the wire in the overlapping times, after 6, 12, 18 seconds in my example?

Does the multiplexer sends data from both channels? If so, how could someone distinguish between the senders? And if they are marked, what's the point of the frequency here?


texts: How much open circuit voltage can a C.T. generate if burden is removed

texts:
The CT types I'm thinking of are those used for the general monitoring of household currents. Myth or truth, will a regular CT (in an otherwise normal and suitable current monitoring situation) generate thousands of volts on the secondary if the burden is removed?

A CT is a step up transformer and the biggest turns ratio I've come across is 5000:1 so potantially, with 200 mV AC on the input, the output could be a thousand volts. But how easy is it to generate 200 mV RMS at 50/60 Hz on one primary turn? The inductance of the short length of cable that passes through the core is going to be in the micro-henry range and, at 60 Hz, 10 uH has an inductive reactance of 3.8 milli ohms. That implies a current of about 53 A is needed. This is significantly above most household circuits of course.

For most small CTs (I'm thinking ones that are used for AC household current monitoring) if the burden is removed, the core is very likely to saturate and this means magnetization inductance falls down to tens or hundreds of nano henries. The knock on effect is that you might generate a few tens or maybe a hundred volts on the output.

So, is this an urban myth or can regular CTs used for monitoring household AC currents potentially produce thousands of volts when the burden is removed from the secondary?


texts: Unstable relay when using single power source

texts:
I am trying to control a 5V fan using an ESP01 and a relay module from LC Technology.
The setup works when I use 2 power sources but my setup requires a single power source which is unstable. The relay turns on but turns off after a couple of seconds.
Stable setup:

Unstable setup:

I do not know all the electronic terminology, which has made it very hard to search for a possible solution. I hope someone here can help with the missing pieces.
The USB PSU supplies 2.5 amperes, which should be more than sufficient.


texts:
I have a test light that has two wires, one connects to B+ and one to ground. You touch the test light on a component and the test light LED shines red if it finds power and green if it finds ground. I want to find the current draw of this light so I connected an ammeter in series: ammeter red lead connected to tip of light and then I touched the other lead to battery ground or positive. But I'm not getting a reading, even on the microamp scale. What could be the cause of this? This test light is unusual in that it connects to both batt posts, could that be an issue? I guess you could say it's connected in parallel to the battery.
Thanks for any help!


texts: Can overshoot current from DC/DC converter damage LED lamp?

texts:
I'm building buck converter to drive led lamps. It consists of microcontroller, PWM generator, buck-circuit and current sensor. Microcontroller knows what target current should be and sets duty cycle basing on current sensor results.

The circuit, powered with +48V at VIN should drive led lamps with wide voltage and current ratings. Current limit is set in uC, independently for each lamp. Output must be filtered for as-low-as-possible ripple, because lamps are pretty far from the driver and I want to reduce EMI.

First simulation: 30kHZ PWM Frequency, 50% duty cycle, 1mH inductor, 47uF capacitor. With this circuit I want to drive 2.5A led strip.

However, in simulation, I can see very high overshoot current during first 2ms of operation. After that current is pretty stable.

I can't just put passive limiter there, because I have to retain ability to set output current.

Now, my questions:

Will such current raise (3.6A for 2ms) destroy 2.5A rated led strip?
How can I prevent such effect?
What can I do to achieve better filtering of output current?
Is there any way to reduce inductor size? With 100uH I get lots of ringing on drain
How can I improve the circuit?


texts: How will I know the power [dissipation] of resistor when buying resistors?

texts:
It is very basic question for many people. It is very easy to predict the resistance of a resistor with multimeter, but sometimes it comes with resistors which are slightly larger in size, such as, diameter 5mm, length 15mm and diameter 7.5mm, length 24mm.

I get confused when buying resistors as power because there are some catagories 2W or 3W or 5W. How can I measure or is there a formula or table to learn the power [dissipation] of resistor.


texts: Voltage divider in voltage mode control of Buck converter

texts:
What is the need of voltage divider in buck converter?

I am not able to understand that why can't we connect output voltage as a feedback voltage to the error amplifier


texts: Replacing momentary button/switch on monitor control panel

texts:
There is a button that toggle inputs on my monitor and the very thin top dome/bubble came off and not I can't really press it to work, though if I use a flat head screwdriver (the diameter of the metallic circle in the button), I can make it work but it's a real PITA to do it a few times a day.  I couldn't fine any of these exact buttons but I have similar ones from another monitor that are just slightly different and I think the size/spacing is close enough to work but IDK how to test if this is the right kind of button or if it wil work at all.

I'm worried about fit, b/c it might be off 7-10 thousandth's in one direction and 3-5 in the other, but they are pretty darn close.  I could always use some very fine wire and connect the button off the board b/c the monitors have been de-bezeled & on a custom mount so the boards are attached to the side of the mounting.

The biggest issue is connecting the lead the way they are needed and IDK how to test a button/switch like this.  Here's a pic of the two boards and I labeled them as best I could. I showed where I touch the broken switch to get it to work and the line is the relative size of the flat head or angled tweezers I use.


texts: UART pins interfacing with Barcode without handshaking signals

texts:
I am concerned about bar code interface with LPC1768/LPC1769 controller.. If I use only UART-TX, UART-RX, GND pin of controller only to interface with barcode scanner module which has UART or RS232 option( without mapping handshaking signal),
i) is it possible to communicate with barcode device.
ii) What should I do with RTS/CTS if they are not used.


texts: extending very short voltage peak with capacitor?

texts: I want to measure the hight of a very short voltage peak using an analog input It does not have to be very exact. the duration of that peak is between 1 and 2 milliseconds, is it possible to extend the duration a bit using a capacitor? obviously it won't be parabolic anymore but that is not a big problem, the only requirement is that it is gone after about 50ms is this doable?


texts: When do I use fiducials for individual components on a PCB?

texts: Obviously the panel needs fiducials, and I also place three of them on each PCB. Some IC footprints however also show local fiducials. I've seen them for instance for certain TQFP footprints. When are they required?


texts: accurately move an object in linear steps with electro motor

texts:
How would you tackle the problem of moving an 1-2 kg object in a linear fashion from point A to B to C and than back to point A and so on? Points A,B,C are fixed and require high accuracy. This image shows what I mean:

I am a skilled developer, but never learned how to connect programs to physical world. I guess I would need 2 electro motors and a strap between them, but I don't know how to program the motor to behave in the way I want, nor how to move the object. I have access to Raspberry PI and I could also get Arduino. The best option for me would be to get a commercially available tool that does what I need, but I haven't yet found one.


texts: What are some good methods for adding charging control/signaling for a docking wireless system with a rechargeable battery?

texts:
I'm working on a device that will dock to charge very similarly to a cordless phone.  The dock outputs 5V DC, which is already very low risk, but I would prefer to add a control pin that turns on the 5V DC output only when the device is connected.  I contemplated having the wireless device's MCU output a signal on the control pin that would tell the charger's MCU to enable charging.  The problem with that idea is that there will likely be times where people don't recharge the device for long periods of time and the battery charge might fall below the threshold to power the MCU.

The goal is that the 5V DC power will not be falsely enabled by someone dropping a paperclip or other conductive object across the charging and control pins.

What are some good options to investigate for the charging base to detect the presence of the wireless device without the wireless device having its own power?


texts: Need help identifying wires on 3-phase single-volt AC motor (6 leads)

texts:
I'm far from an electrician. Just a guy trying to get some new life out of an existing piece of machinery.
See the image below, this 5HP motor comes from a heavy duty commercial treadmill. Based on the fact that it has no start capacitor, 6 leads, and that heavy flywheel on the right this is a 3-phase single-volt motor.
The labels originally were W,V,U but some of them were scratched off and unreadable. But there's two additional wires both black and missing labels, and the green for total of 6 wires. I've labeled the black wires A,B,C,D,E and measured them using ohms setting on a multimeter:
* A<->B: nothing
* A<->C: nothing
* A<->D: 0.6
* A<->E: nothing
* B<->C: 2.2
* B<->D: nothing
* B<->E: 2.5
* C<->D: nothing
* C<->E: 2.5
* D<->E: nothing

My questions are:

how do I restore the original labels of W,V,U from the information above?
if 3 wires were W,V,U and the other two had no labels remaining, what purpose are the other two wires?
assuming i identify all the wires are correctly labeled, any quick way to test the functionality of this motor before wiring it to a control board?


texts: Detecting the over current and cutting off the supply

texts:
I have a load which draws current from the source that is less than 500mA. If by any chance, the load becomes heavy and starts drawing a current which is more than 500mA, this over-current should be detected and the supply should be cut-off to load.I need a solution using no ICs ie. only with discrete components.

I have already tried with transistor and also been able to detect the over current, but i am struggling to cut-off the supply to the load.


texts:
I am a beginner in Electronics. I would like to clarify if my understanding regarding LEDs is correct.

Suppose that we have an imaginary battery with no internal resistor that provides 2 volts. Assuming that we have a LED with forward voltage and current 2 volts and 10mA respectively. The question is can we simply light the led without a resistor? My assumption is yes, since the LED will have a voltage drop of 2 volts, and the current will be 20mA.

My questions stems from the fact that there are many many sources out there, mentioning that a LED will try to gather as much current as possible and burn out in the end. This is wrong i feel or at least not very accurate.  In general, the current that a LED will try to obtain is not the maximum available by the battery, but the current as specified in the i-v curves of the LED.

Also, just to note, I am not asking if a resistor is required or not in case of a battery that provides enough voltage. Its more than clear to me that it is required.

Is my understanding correct?


texts: How is Chassis ground connection implemented for an input cable with TVS diode protection?

texts:
I believe my question is different enough in specifics to Is it better to connect ESD (TVS) Diodes to chassis ground or signal ground? to warrant a new question.
According to Electromagnetic Compatibility by Henry Ott, it is advised to shunt incoming transients on external IO lines to chassis ground using TVS diodes. This should be done as close as possible to the IO entrance, minimizing the distance on the PCB that a transient would travel. It also shows that the chassis ground should be connected to circuit ground, presumably at a single point to avoid ground loops. He also recommends having the chassis ground connected to the chassis at multiple points, minimizing inductance.

Further, Mr. Ott says "It is therefore, important to establish a low-impedance connection between the chassis and the circuit ground in the I/O area of the board." This was in reference to preventing CM noise from conducting out of the cable, not WRT transients coming from the cabling.
My question is, how and where is the connection between chassis ground and circuit ground made? My concern is, if it is made at the IO section, with a low(ish) impedance connection, the transient event will still have an effect on circuit ground. That would make it similar to if the TVS's were instead just connected to circuit ground instead.
An option I could see is making the chassis ground -> circuit ground connection with a resistor, to make that a higher impedance path than the TVS -> circuit ground. But I can not find any information on this method.


texts: What is Virtual Memory and Virtual Address space

texts: I am  not able to get, what is virtual Memory and Virtual Address space. In which situation it will be used. I have referred wiki page, but I couldn't able to get it. Can any one give one simple example for this, when and how the VM and VAS is used.


texts: Electrical contacts overview ( switchgears )

texts:
I'm currently working on an overview of contacts used in switchgears adjusted to medium voltages. What's more, I need descriptions of the contacts' shapes. I've tried to find some features of technical solutions I found but with a poor result.

It seems that nowadays everyone uses 2 contact's types :

RMF - Radial Magnetic Field
Contacts with dissipation difusion of the arc

It doesn't matter if it's vacuum breaker or insulated with SF6 one. I managed to find something more but it's still not enough.

Do you have any ideas where I could find more of the contacts ( shapes ) which are out of use ? ( historical, old devices ) The greatest difficulty is with finding so called inseparable not movable contacts and inseparable movable ones.

I would be very grateful for any tips/advices to this topic.

P.S. I've spoken with some manufacturers and the biggest companies in this trade but they all sounds quite similar.


texts: Determining wattage of a variable resistor in series with a known resistor

texts:
I'm trying to determine the wattage of a variable resistor Rvar which will be wired in series with a 2 ohm resistor Rs as in the above figure. Rs can handle high currents.

The power supply V1 is 24V 20A power supply.

I follow the following logic:

If Rvar is set to 0 then it disspates no power.

If Rvar is set to 10ohm it disspates I^2*R = [24/(10+2)]^2 * 10 = 40W

If Rvar is set to 6ohm it disspates I^2*R = [24/(6+2)]^2 * 6 = 54W

If Rvar is set to 2ohm it disspates I^2*R = [24/(2+2)]^2 * 2 = 72W

If Rvar is set to 1ohm it disspates I^2*R = [24/(1+2)]^2 * 1 = 64W

It seems like we need to use maximum power transfer concept which happens when Rvar = Rs when sizing the wattage of a variable resistor or a potentiometer.

So in my case I should use a variable resistor wuth 72W or more power rating?
Is my way of thinking right for variable resistors and potentiometers in such circuits?


texts: What is just the plastic base of pin headers called?

texts:
What is this part called? It's the plastic part of a row of pin headers, by itself.
I got a strip of these with a kit once but I don't know how to find more of them.
They're useful because stacking headers are often a bit too long.


texts:
I've generated the bitstream file for my device, which steps should I take to compile the .ACE file, I could flash my device with?

I'm using Xilinx ISE 10.1 with Virtex2 over an VME interface


texts: I have a DAC that outputs between 0-5V range but lacks the current output, that I do need to get more out of it, it provides approximately 10mA at tops. I need to boost the current by a transistor but to choose it I need some advice. What I am trying to say is that, whatever output I give from DAC, I need the same voltage but should be capable of providing higher currents upto 500mA. To achieve this I wanted to ask to experienced users regarding the topic.


texts: Selecting the right PMDC motor and battery

texts:
I'm looking at generating electrical energy from a mechanical input being used to rotate the shaft of a Permanent magnet DC motor. However, i'm a bit stuck with selecting the right motor and battery to store the energy in(and everything else needed between)

My average mechanical input to the motor will have a power of approximately 200W, and the shaft RPM would be in the range of 500-1500. However, the RPM will be prone to fluctuation within this range (It's an ergometer so RPM and Torque will vary throughout each individual stroke)

I plan to store the produced electrical power in a battery. However, i'm not very clued up at all with the electronics side of things.

My first question is: Is it best to use a Permanent magnet DC motor as a generator, or an Alternator? I'm not quite clear which is best in this situation and why. Since I will be storing the energy in a battery, i have been going on the assumption that a DC motor is best?

Secondly: What other components are needed in the circuit between the motor and the battery? And what kind of efficiency can i expect from each component (Very approximate?)? IE if i put 200W in, how much can i expect to actually reach the battery?

Finally: Is it possible to charge a battery with an unstable voltage? or would this present problems and some method of controlling the voltage would be needed?

Thanks!


texts: Can I charge multiple SLA batteries at once like this?

texts:
Simple question from a beginner. I 'drew' a schematic diagram to show my idea of how I could charge multiple SLA batteries with a single charger. Would this work if I solder the wires together as shown?

If this approach does not work, do you have any other recommendations for how to charge multiple SLA batteries with one pair of wires? I don't want to charge one, unhook, charge another, etc.

Thanks!


texts: Does input impedance of an isolation amplifier or a transformer have impact on common mode to differential mode conversion?

texts:
I have a question where I can only explain it clearly by an example. It is about conversion of common-mode interference to differential mode due to overall system imbalance.

I will use below two models where a common mode voltage is applied through a cable to amplifiers in both cases. In Figure 1 differential amplifier is the receiver; and in Figure 2 an isolation amplifier or any system which has isolation like a transformer is the receiver.

Let's first look at Figure 1. Rs1, Rs2 can be source output resistances and C1, C2 can be the cable's capacitance to the ground. Rin1 and Rin2 represents the input impedance of the differential amplifier. Here it is apparent that if we want to estimate how much Vcm is converted to differential mode then we need to know Rs1, Rs2, C1, C2 and also Rin1 and Rin2. We can also see that even Rin1=Rin2, still value of input impedance have an impact on the value of common mode to differential mode conversion.

Now let's examine the case for Figure 2 where the isolation amplifier is used ans same Vcm is present. For simplicity I tried to model as it has input impedance Rin and parasitic isolation capacitance as Cp1 and Cp2 as shown. In this case it is to me apparent that Rs1, Rs2, C1 and C2 again determines the conversion from CM to DM. But it is not very obvious whether the value of Rin has impact on the value of the common mode to differential mode conversion.

Regarding Figure 2 my questions are:

It seems the common mode currents will not flow through Rin but they will flow through Cp1 and Cp2. Is that correct? If so does that mean the input impedance value of the isolation amplifier has no effect on CM to DM conversion and act almost as an open circuit to the common mode voltages?


texts:
I'm currently using a boost mode constant current LED driver IC LM3424. I used a MCU to PWM dimming the brightness of the LED, and schematic of LM3424 part is almost the same as it in LM3424 datasheet.

And this is my detailed schematic(if it is needed...)

My problem is that two of my assembled PCB board didn't working(I made three of them). The good news from what I measured is that, the problem is not the detailed DC/DC technology, but the power supply of the chip(I think...). Measured with an oscilloscope, I got no readings(zero volt) from LM3424's VCC(pin 16) and VS(pin 11). From the pin description, I got that:

I also read the block diagram, and got the idea: if the chip is not damaged, it should at least have normal readings on VCC because the 6.9V LDO regulator will not turn off with both VIN and EN present(in my case, I wired them to 9V).

So is my view right? Should I just go for some new LM3424 or my conclusion need more measurement? Any suggestions is appreciated:)


texts: Does the physical size of through-hole ceramic capacitors relate to voltage rating?

texts:
I am sorting through some ceramic capacitors and reorganizing them. I came across a number of capacitors with "82" on them (at left), which I assume is 82pF, but they are physically larger than even my 0.1μF capacitors (at right).

Does the large size of these capacitors relate to their voltage rating (or something else), or did I misinterpret the capacitance value?


texts: Replacement of 2N3822 and 2N5640 for a 0-12v adjustable power supply

texts:
I'm trying to make an adjustable 0-12v 0-500mA power supply. I'm using the following schematic as a base (I modified the 240Ohm resistor between Vout and Adj of LM317 2, and the RSC resistor):

The 2N3822 and 2N5640 are not available in my country. What could I use as a replacement? I also tried looking for the 2N5485 but couldn't find it neither.


texts: How to calculate the range of a RC transmitter

texts:
When searching for a transmitter for a RC application in most of the cases they don't provide anything about the range of the module. Just power and the frequency.

The Tx power must relate to the range. But I'm not sure how the Tx frequency can relate with that. Any idea about that?

How can I get some idea about the range of the module considering the provided details? is there any equation or something??

(For example please refer to this module on eBay)


texts:
I'm building a lighting system for a bike, powered by a dynamo (typically rated 6V, 3W max). The load will include LEDs and a bit of logic (such as N555/ATTiny85 for blinking, etc.). I also plan to include some form of short-term energy storage (for red lights): either a supercapacitor or a small lithium battery.
What is an appropriate choice for rectifying the 6V AC input? Obvious choices are:

a full-wave diode bridge rectifier (pro: easy and cheap, exists as a single-package; con: but at a low voltage, that 1.5V loss stings a bit);
a Schottky diode bridge (a bit more efficient, a bit pricier, I don't believe it exists as a single package);
a simple MOSFET bridge, which I used in a previous iteration of this circuit, but it apparently cannot charge a capacitor (although I believe I used it successfully for that purpose in said previous circuit...), which can have a low drop but is more cumbersome;
a MOSFET bridge driven by a LT4320: I've never used this component, and it apparently needs at least 9V to work. Also, I've never soldered SMD yet.
there seems to be a dedicated chip, FDMQ8203, but that is a bit expensive (incl. shipping cost) for a chip I'm not sure to be able to solder (tiny MLP package).

Did I miss any other rectifier circuits, and is my evaluation of the pros and cons of each type of rectifier accurate?


texts: Bridge rectifier outputting 338 volts DC with 120 volts AC input

texts:
I am measuring the live voltages right now and am seeing these numbers. I thought 338 volts DC was the result of rectifying 240 volt AC?

I understand that 120 volts AC is the Vrms reading and that the Vpeak reaches up to 170 volts. I just don't understand how I'm getting 338 volts from 120.

The number ~338 comes from the peak voltage of a 240 volt RMS:

\$240\sqrt2 = 339V\$

I am using one of these types of rectifiers (not this exact one because I cannot find any details about the markings on the one I have it says PEC 5079:

The voltage read between the two center pins is 120. The DC voltage read from the outer pins on my DMM says 338. This seems impossible? Could it be my meter is faulty? It has always been decently accurate for everything else and I've had it for over a decade.


texts: Flooded lead acid batteries in series and parallel - voltage drop at negative terminal

texts:
This question is a continuation of my previous question :
What is the best way to combine multiple batteries (flooded lead acid)?

I have a battery bank of four 150 Ah 12 V flooded lead acid batteries connected in series and then parallel to achieve 24V 300 AH capacity. The batteries are charged by solar panels in the day and used to power connected load of approx 350 Watts at 230 V AC, through a 1.5 KVA 24 V inverter. The batteries are charged to 25.8 V  by evening.

The inverter usually trips after about 8 hours of operation due to low battery. My problem is that at the time of tripping,  the voltage in the (both) batteries to which the negative terminal of the inverter connected is 8.5V and that of the batteries where positive terminal is connected is 12.5 V. The inverter trip at 10.5 V which is the average of both values. The cables interconnecting batteries are of same size. I tested various combinations to see whether any particular battery is causing the drop but not found any thing abnormal.
I Think this is highly abnormal. How can voltage of a 12 V battery can go as low as  8.5V ? The batteries where the positive of inverter is connected are seem to be in full power even as the inverter trips.why no power is drawn from the positive connected batteries ? What may be causing this sharp drop ?. How can I prevent such sharp drop in these batteries?.


texts: Powering condenser mic while getting the signal

texts:
http://www.afrotechmods.com/groovy/amplifier_tutorial/amplifier_tutorial.htm

Look at the extreme left part of the circuit above seem to power the mic by 9v through a 5k Ohm resistor that powers the mic through same pin that spits the signal wont it cause distortion in the signal


texts: OrCAD - diode characteristic with different temperatures

texts:
I have a basic circuit with diode, resistor, and a voltage source.
I am getting the following error when trying to change the X Axis variable to Vd (diode voltage):

ERROR(ORPROBE-3217): Only 1 expression allowed for the X variable.

I have set three different temperatures in Temperature (Sweep).
Default variable for X Axis is the voltage source, and when trying to change it to V(D1) which is a diode voltage, it gives the above error.

My question is how to get diode characteristic (or any other characteristic) Id=f(Vd) when multiple temperatures are used in the same simulation?


texts: Measuring old capacitors - what could cause large deviations?

texts:
I'm measuring an assortment of old electrolytic capacitors ('elcos') to see if they are still okay, using my digital multimeter (a simple Duro AL-205). I noticed that most of the values are higher than the rated capacitance but that's okay since I know tolerances are usually in the -20% to +50% range.

But when I have an elco rated at 320uF, (yes, 320 not 330) 6.4 Volt but it measures as 844uF, I'm sure something's broken. Is there some fault mode in elcos that can cause higher-than-rated values? I'm careful  not to touch the terminals with my fingers when measuring, so any parallel resistance does not influence the result.


texts: Finding the voltage range in a series circuit

texts:
Given a DC circuit with 3 resistors connected in series and the following information:

The resistance of R1 is 2 ohms.
The voltage over R2 is 20 volts.
The power dissipation on R3 is 25 watts.

what is the range of all possible voltages on the voltage source?

I formulated the voltage as a function of current:

$$V(I) = 2I + 20 + \frac{25}{I}$$

I don't know how to keep going from here


texts: Can Orcade (PSPICE) actually simulate MOV(Varistors)?

texts:
I am using Cadence-Orcade Lite. In it I have a circuit in which I want to note the behaviour of varistors (MOV, PSPICE models exist in Orcade for various varistors).

I am using LS40K680QP/EPC Model of a varistor and I want to depict the behavior of this device when transients in ac supply are applied.

I have connected an ac source in parallel with some load. When I simulate it, it doesn't have any effect on signal voltages even when the voltages are beyond its clipping voltage (or rated voltage from datasheet). It should clip voltages to the maximum operating voltage of varistor when supply voltage have transients in kilo volts.

I want to know, if there is some method to make this mov depict its actual behavior, or does it just not simulate  real life?


texts: issue with creating a new line in hyperterminal

texts: I am sending few data to the hyperterminal via UART. When i send a new line character, the data moves to the next line but it starts from the point where the previous data is stopped. The cursor doesn't move to the beginning of the line.I have tried many times using ASCII 10,11 and 13 and it still doesn't work.How do i fix this?


texts: OP07 - Input Bias Current vs. Differential Input Voltage

texts:
In OP07's datasheet, i find the 'Input Bias Current vs. Differential Input Voltage' chart. Can anyone give some explanation about the chart. I notice OP07 has input protection diodes at the input. So i think the chart has some relations to these diodes.

The 'plateau' around zero differential input voltage corresponds to the case when the input diodes are off.

The straight slope line show it's 'resistive' beyond some input voltage.  So it correspond to the case when input protection diodes are on. The datasheet states the differential input resistance only 50M Ohm, but if i calculate from the chart, it shows the input series resistor R3 (or R4) will be 600M Ohm or so.
Am i right?


texts: How to change a component value on hierarchical structure in altium

texts: I designed a Hierarchical structure in Altium. I need a component value becomes different from other sheets. However, by changing the value all other sheets get the same value. As you can see by changing a resistor value on TCP sheet other sheets change the value of their components based on the other sheets. How can I solve this problem?


texts:
What's meant by this question?

"You need at least four states to exploit the advantages of a Mealy machine
over a Moore machine."

I'm trying to wrap my head around this but I'm not sure "what" advantages are being spoken about. I know a
1 state Mealy Machine can have a possible 2 state Moore Machine.
2 state Mealy Machine can have a possible 3 state Moore Machine.
etc...


texts: If I have a device that transmits data over Bluetooth, is it possible to get at that data via a different device with my own custom code?

texts:
I am looking at building a tyre pressure info system for my car, but would like to make use of the existing receiver and transmitters that screw onto your tyre's valve stems.

A model exists that transmits the data over Bluetooth, which you are then meant to download an app to view the data.

I am wondering if it's possible, if I had a Bluetooth chip on my computer, to tap into that data and build my own custom interface for it? Is it complicated or something someone in my experience could do rather straightforwardly (software engineer with some electronics knowledge)?


texts:
I'm using FPGA DE2 board cyclone II from altera (for PWM generation) to control a DC chopper via ARCAL 2108 driver ;The problem is that the FPGA GPIO output gives a 3.3V but the driver is +15V input .
I used a buffer IC (CD4009 ) to shift the voltage from 3.3V to 15V but when visualising the buffer's output with an oscilloscope I get a Vmax=15V(using measure) but the voltage diagramm has an offset!

Can any body help me !!!I thought to use an IC level shifter or even build an analog circuit (using transistors ,R,C...)

update:

I think I have found the right IC MC 34152 its high speed dual MOSFET. I've just tried it on scope but not with FPGA.


texts:
I have a machine running three 12v solenoid coils. Currently, control is carried out by manual switching of the negative through SPDT toggle switches. The coils all have a positive 12v common.
I am wanting the ability to additionally control the coils through Arduino with serial comms. As such, I have built a basic PCB consisting of a Nano, N channel Mosfets, diodes, voltage reg etc. I have then retrofitted this PCB into the existing machine wiring using a DPDT toggle ON-ON switch (see attached - apologies on the horrendous drawing!! Should do the job though).
When I flick the DPDT switch to power the nano I can successfully control the coils through a basic program. Mission accomplished.... or so I thought.
Initially I was getting a 0v leak through the voltage reg causing the coils to energise slightly (in manual mode), but wiring the voltage reg 0v to switched 0v fixed this.
When controlling the coils manually through the SPDT toggles, there is a back feed into the PCB (via mosfet drain i think) which lights up the LEDs on the Nano as long as the toggle switch is held. This caused the Nano to get hot, smoke and fail.
Is there a way I can provide some sort of back feed protection to the Mosfet drains when operating the coils through the manual switches? I thought of using diodes with anodes to drain and cathodes to coils, but then I stop the 0v return to battery when trying to operate the PCB.
I cant help but feel this would be much easier if switching the positive, but unfortunately in this case this is not an option.
Any help on this would be greatly appreciated.
Thanks in advance.


texts: Measurement of RF Signal strength / phase difference

texts:
I would like to measure the signal relative strength and phase difference of two bluetooth (BT) receivers and I found a chip that will do exactly that, AD8302.

But I don't know how to setup the circuit. As far as I know the BT receiver will transfer the received RF signal to UART or USB, so my question is that how can I extract the received RF signal from BT Rx at first and send it to the AD8302?


texts:
I've put together this circuit, and (with some help from EE SE) it's working great.

I have it wired like this:

where the diode comes first off the middle transistor pin, and then the motor negative comes next. The motor negative lead and diode are not touching (except that they're in the same vertical rail).

I understand the diode is in this circuit to handle discharge of the 12V solenoid. If I wire the negative lead first, as so:

would this be equivalent to the above or does it matter where the diode is in relation to the negative lead?


texts: Can I use BTL audio amplifier IC in single-ended output configuration?

texts:
I am designing a widget that has to have a speaker output (low power, between 1W and 2W, 8 Ohms, low-quality) with the limitation that one end of the speaker must be grounded.

There are lots of audio amplifier ICs to choose from, but all I could find have BTL outputs (they drive both ends of the speaker). Can I use such an amplifier (for example Class-AB TPA6211A1 or Class-D PAM8012) in a single-ended output configuration? Will I only loose maximum power output?

I have regulated 3.3V and unregulated 7.2V (2x li-ion) available. The signal source is a 3.3V MCU. Its DAC can generate single-ended and differential signals. The MCU also has I2S interfaces.


texts: principle about SPAD for ToF ranging module from ST

texts:
My colleagues are using VL53L0 from ST which is one ToF ranging module. I am trying to understand the principle about the SPAD(single-photon avalanche diode) and have read many materials on it.

From one paper, it reads the output of a SPAD is an electrical pulse for each detected photon. Does it mean that the reflected photon won't arrive simultaneously? How much is the interval between arrival of two sequential photons? Can the digital circuitry detect the arrival interval?


texts: Motor Sizing and Wiring Diagram Help? My motor has a wiring diagram but no ID tag

texts:
Here is a link to an Imgur album of my motor and its wiring diagram

I have a motor that I'd like to wire.  My two questions are, how do I determine its operating parameters, and how do I use its wiring diagram to wire it?

My Imgur link has all the pictures I took of it, as well as descriptions of each picture.  I'll still elaborate here:

It unfortunately has no ID tag on it, so I don't know what horsepower or voltage it is. The sticker on it says it is "Farm Duty", and it has a wire diagram sticker on it, so I believe I could wire it if I learned how to decipher the diagram.

It doesn't have any capacitors on it, which I think makes it 3-phase?  But, the wiring diagram calls out both "low voltage" and "high voltage" configurations, which leads me to believe it is rated for 120V or 240V circuits - which is single-phase?  If someone could help me understand this, that would be great!

I have general wiring skills and feel confident I could safely wire this motor with enough learning.  Thanks for your help!


texts: Maximum current input of an LM2596 step down converter

texts:
I begin in electronic, so sorry if my question is bad.

Can a LM2596 step-down converter accept 12V 8A as input ?
I can read everywhere that the maximum output current is 2A or 3A but nothing about input current.

I have a 12V 8A DC Power supply to power a 5M 5050 LED strip (I know 3A is enough) and I want to power my Wemos D1 Mini Pro with 5V.

Scheme gonna be like this :

Thanks for your answers.


texts: What is the order of power intake across a GPU's power connectors?

texts:
On an Nvidia/EVGA 3080/3090 FTW3 GPU, there are three 8-pin PCIe power connectors. How does the "ordering" of power draw work across its 3x power ports (+ its PCIe slot)?
For example, if a 3080 FTW3 suddenly needed 450W of power, how or in what order would that be drawn: would it grab as much power as it can get from one power source before moving onto the next, e.g.:

75W from PCIe slot (..75W total)
-> 150W from 8-pin #1 (..225W total)
-> 150W from 8-pin #2 (..375W total)
-> remaining 75W from 8-pin #3 (..450W)

..? Or does the GPU draw power through all the ports in parallel? What happens if one port can't supply power equally as the other two?
As an example: if you have two 8-pin PCIe power cables + one 6-pin -- given 6-pin cables will only have 75W max drawn over them -- what would happen as far as power draw? Would it matter which port the 6-pin cable was plugged into? How would the GPU respond in a case like this, or if the 6-pin cable was alternated between ports 1-3?


texts: I have a 90 volt gearmotor and would like to use an AC voltage twistlock style plug for ease of motor replacement. Is this an acceptable use (per code) or does it not make any difference? Thanks


texts: How to build a light sensor for PWM dimmed light (for comparison against CC dimmed light)?

texts: I am working on a project in which I need to find a PWM duty cycle to dim an LED to the same brightness level as an LED being dimmed with CCR. Initially, I was considering using a camera for this: I would take a picture of each LED, and compare the intensity with photo-editing software. I am not sure how accurate this would be, though. I was wondering if there were any devices out there (light sensors, etc.) that could help me achieve this.


texts: Check the value of FSL_M_Control in the MicroBlaze

texts:
I wrote a hardware accelerator which communicates with a MicroBlaze over FSL. In the Microblaze C code I would like to use putfsl() in a loop until the hardware accelerator signals the MicroBlaze that it should exit the loop:

while( <FSL_M_Control is not 1> )
{
    putfsl(*foo, 0);
    foo++;
}

Is it possible to get the value of FSL_M_Control and use it to exit the loop? If it is how could I do that?


texts: Why aren't pins on microcontroller grouped together, close to each other?

texts:
Simple question, the curiosity is killing me.
Why do microcontrollers (and other IC also, like RAMs) have pins not grouped together?

Like in STM32, for example you have portA and it has 8 bits on one side of IC and the other 8 bits at the opposite corner of IC... Why? It make routing PCB much harder. What is the reason or purpose of such alignment? Why couldn't they put it next to each other?
And why do 32-bit uCs (like STM32) have 16-bit wide ports, when they could have 32-bit wide?

The same goes with RAMs - address pins and data pins are scattered almost randomly over the IC. Why?

Inside the IC there are plenty of routing layers, so what's the reason they couldn't add one more to group pins in some logical order?


texts: Li-Ion battery status indicator LEDs with zener diodes

texts:
I've just inherited a project from another engineer with zero overlap. Looking at the schematic it seems that they've attempted to include two battery status indicator LEDs through the following circuit:

Can I have some help figuring out what's going on? The battery is here, a 14.8V Li-Ion with 12V cutoff.

The green LED is straight forward but I'm struggling with the red. I don't have the LED specs. D1 has Vz = 6.8V which forces 6.8V to the LED anode. If we assume 1.8V across the LED then we have 5V at the LED cathode and across R4. Vz = 7.5V for D3, so the LED won't have enough voltage unless Vbat falls below 12.5V?

But that means the max current through the LED will be 5mA, which seems very low. Is this interpretation correct?

I will probably do a redesign, but I would still like to understand.


texts: Should I spray some flux on my board before putting it in the reflow oven?

texts:
I am using Tin-Lead solderpaste to make my prototype circuits. This is the exact solder paste:

  ALPHA OM-5100 (https://alphaassembly.com/Products/Solder-Paste/OM-5100)

      Alloy: 62Sn/36Pb/2Ag, 63Sn/37Pb and 62.8Sn/36.8Pb/0.4Ag (NT4S, Anti     Tombstoning Alloy)

      Powder size: Type 3, (25-45 µm per IPC J-STD-005) or Type 4 (20-38µm).

I use a stencil to apply the solderpaste. Next, I place all the components one-by-one.

The solder paste contains flux. However, I'm worried the flux evaporates while I'm placing the components. It generally takes several hours - up to 8 hours for my latest PCB - to get all components in place.

I've got the impression that the solderpaste doesn't "flow" sufficiently. For example, I would expect slightly misaligned resistors and capacitors to straighten up when the solder melts. But that doesn't happen.

Another example: Imagine some solder paste that isn't applied very good:

During the reflow process, I would expect it to flow like this - as if it is attracted to the copper pads and repulsed by the naked FR4-material or coatings(where no copper is present):

But that doesn't seem to happen either.

Should I spray some flux onto the board before I shift it into the reflow oven? If yes, what spray would you recommend?


texts: Unknown problem with I2C on Spartan 3-E {VERILOG}

texts:
I have a Spartan 3-E board.I was using the inbuilt Xilinx SRL 16 (16 bit concatenated shift registers) for I2C communication.I verified successful implementation by displaying the number of "Acks" received on LEDs i.e (I had an internal counter which would increment if SDA was pulled low during the 9th clock cycle).My problem starts when instead of using the Xilinx SRL primitive, I built my custom 8bit Left Shift Register.I had to do this because the system has to be kept idle for some time and only a few specific registers need to be programmed so I can't rely on the auto increment feature.Any way, I haven't been able to verify I2C comm. as before, despite keeping all other aspects the same and ensuring absolutely zero difference between simulation patterns of the earlier successful design and this new one.
I am sharing my code  and would be extremely grateful to anyone who could have a look.

------------------8-bit SRL----------------

module CustomSRL(
    input [7 : 0] Value,
    input LE,
    input CE,
    input clk_i2c,
    output Q
);
reg [7 : 0] SRL_8;
always @ (posedge clk_i2c)
begin
    if(CE) begin
    if(LE) SRL_8 <= Value;
    else   SRL_8 <= {SRL_8[6 : 0],1'b0};
          end
end
    assign Q = SRL_8[7];
endmodule

UPDATE :

I was just experimenting and realized that when I replace my custom Shift Register (provided above) with the SRL16 E primitive, the design works.This is very surprising.I tried to make small changes to the logic by using a simple register with a Load Enable and a multiplexer to single out the bits.However, that doesn't work either.

Why is it that the SRL16E primitive design works but not the others? I have provided code for my shift register (serial in,serial out, parallel synchronous load) module above.The simulation results are the same for all three designs.

Can anyone offer an explanation for this apparently bizarre behavior?
Sending Values to 8 bit Shift Register :

always @ (*)
begin
    case (Byte_Counter)
    0 : LUT <= 8'h56;                                   //Device Addres
    1 : LUT <= i2c_address;                         //Register Address
    2 : LUT <= i2c_val;                             //Data
    5 : LUT <= 8'h7E;                                   //STOP & START
    default : LUT <= 8'hFF;
    endcase
end

    always @ (*)
begin
    case (Reg_Counter)
    1 :begin i2c_address <= 8'h00; i2c_val <= 8'h02;    end
    2 :begin i2c_address <= 8'h03; i2c_val <= 8'h00;   end
    3 :begin i2c_address <= 8'h05; i2c_val <= 8'h09;   end
    4 :begin i2c_address <= 8'h07; i2c_val <= 8'h07;   end
    5 :begin i2c_address <= 8'h09; i2c_val <= 8'h00;    end
    default : begin i2c_address <=8'h00; i2c_val <= 8'h00;   end
    endcase
end

Variable LUT is loaded into the 8 bit Shift Register on the 9th(when SDA=high impedance) clock cycle.

One thing that I'd like to add is that I tried to register the outputs of the multiplexers before packing it off to the 8-bit SRL by :

always @ (posedge clk_i2c) temp <= LUT;

However, that hasn't worked either, but I do get one interesting warning :

INFO:Xst:2260 - The FF/Latch <i2c_ADV7171/temp_6> in Unit <Verilog> is equivalent to the following FF/Latch : <i2c_ADV7171/temp_4>

As far as I can tell, this shouldn't happen because temp[6] and temp[4] aren't throughout equal.


texts: Questions about an atmega32 serial-bus to RS232 with converter and different logic levels

texts:
I have an atmega32 and a FUM DCF-U atomic clock (signal receiver and decoder) of HKW-elektronik. The µ-controller works with 5V and the module on 3.3V.

I have to build a converter, because the µ-controller only has serial-bus communication and the module has RS232 communication.

I did some research and I found these IC's: MAX232, MAX3323E or MAX3232.
In the datasheets and on ArduinoSoftwareRS232 reads that it needs extra voltages (one + and one -) for some pins. Is this necessary or are the capacitors enough?
And which IC should I use? (First time I need to use these IC's)

And can these IC's being used without a logic voltage converter?

Thanks in advance


texts: Which ammeter to pick for best accuracy and why?

texts:
This is merely a theoretical question.
If we want to achieve the best accuracy possible while measuring electrical current and we have two digital ammeters available from two different manufacturers, which both claim to be accurate by the same order of magnitude, in what way can we determine which ammeter is more accurate? This is one question from my Electrical Measurements book. The only way I can think of is taking multiple measurements with both ammeters, calculating the mean value of measurements for both ammeters and comparing that value to the correct value (best estimation). And whichever one has lower absolute mistake (\$ \Delta I=I_{mean}-I_{correct}) \$ is a more accurate one. Am I right? Or there are other things to consider?


texts: Using a 5vdc solar charger to trickle charge 6 vdc reachargeable 4 AA battery pack

texts:
I am looking to purchase a remote water tank level monitoring system an Aquatel D110 Wireless Tank Level Monitor ( http://www.rainharvest.com/aquatel-d110-wireless-tank-level-monitor.asp ) - it uses 4 AA batteries.-

Can I use a 5v solar charger (power bank) for smart phones.   Can I wire direct from the USB output of the 5v solar smart phone charger to the 4 AA battery pack  of the water tank level monitoring system  (minus the batteries)?  such as a https://www.amazon.com/YOUNGFLY-20000mAh-Waterproof-Dust-Proof-Shock-Resistant/dp/B01IH304ZM/ref=sr_1_11?ie=UTF8&qid=1515518609&sr=8-11&keywords=solar+charger+for+cell+phone


texts:
Can I ask for help in identifying the following SMD component? Package is SOT-25. Marking is bPCGD .
Probably is voltage detector but I dont know his parameters. It is a component of mainboard IP camera YI YHS3017.
I add photos of the mainboard and a diagram of this component that I was able to measure. Pinuot 3 is connected to a nearby coil, pinout 2 is ground, pinout 5 is voltage from power supply (5V).
I`ve looked in many catalogs but it is probably a unique label of the manufacturer. I suspected it might be the BD5242G but it doesn't match the ground pinouts.
Thanks for your help


texts: How to send analog data using FM/FM Telemetry

texts: I am measuring the strain a bicyclist is placing on a bicycle crank arm throughout riding, using strain gages. I would like to send this data (after amplification) off of the bicycle crank arm and to my data processing unit. How can I send the analog output voltage data I am interested in measuring using an FM/FM telemetry scheme. I have looked into VCOs to create my carrier frequency, but does FM/FM require a sine wave output instead of a square wave? Also, how do I then create subcarriers frequencies so I can send multiple streams of data in parallel? Lastly, how do you take these signals and send them off? What is used to create an antenna? Theres a lot out on the internet on the overall flow of how FM/FM works, but nothing in terms of specific electrical components to use.


texts: Problem with high-side current measurement

texts:
I am having strange failures in a high-side current measurement circuit that I have not yet understood. The U3 measurement chip is getting damaged and shorts out. Perhaps someone can help identify potential failure points in this type of measurement circuit?

+VSA is a "safe zone" discrete supply (below) designed to hopefully minimize the chances of this measurement circuit creating a failure point (sigh). It's typically between 3-4V.  M3 lets a very small (microseconds) pulse of voltage (up to ~7-12V maybe) through before the gate turns it off... then M3 is turned on in a slow-start (but still fairly quick) manner.  Because of this, +VSA is potentially lower than S+ for that very short period (That circuit's input is fed from the same point as the top of M3).  I don't see any reason in the datasheet for that to be a problem, though ("Independent supply and input common-mode voltage").

I added D10 and D11 thinking the differential voltage spec of 0.8V was being violated with inrush current... but I've had another failure with even this new design.

It only seems to fail during power cycle events.

The failures seem to be related to parts of the downstream circuitry getting shorted out during/before power on... but in testing only this circuit I can't seem to kill it no matter what I do downstream. It only seems to fail in combination with the rest of the unit.  So, I'm wondering if anyone can identify additional failure modes I can look into.

Here's the datasheet for U3: ZXCT1086 datasheet

+VSA circuit:

EDIT: Ok, so the +VSA circuit above is perhaps confusing. The +24V node refers to the system voltage input at the top of M3 (well, system input after the fuse, switch, GDTs, and reverse voltage protection).  The node after R26 is +24_AUX, which is not the same.

However, I did notice the diodes D10 and D11 are perhaps not clamping to ~400mV like I expected.  They're rated for 410mV forward current, but at 1mA. At even 15mA the forward voltage goes up to 1V. I did not expect that, and I can't believe that this far into my circuit designing "career" I haven't heard of how much they vary by current before. I knew they varied a little, but that's way more than a little. I'm adding the datasheet for the diodes as well. It appears I need to re-think the protection the diodes are trying to accomplish.

Another note: In previous testing, I was unable to force the voltage across R26 to go any higher than 100mV.

Diode datasheet: BAS70H,115 datasheet


texts: Interfacing 3.3V Flex 6000 FPGA to a 5V CMOS DSP (Multivolt IO Question)

texts:
I'm going to interface a 5V CMOS DSP to the 3.3V Flex 6000 FPGA.

This FPGA supports 3.3V and 5V IO according to the below figure from the datasheet:

Since the FPGA I found in stock is the 3.3V version, I must connect VCCINT and VCCIO to 3.3V. The minimum Vih of the DSP is 2V. Is it safe to connect both devices together? I'm afraid this 1.3V (3.3V - 2V) isn't enough to avoid ripples or ringing effects on the signals.


texts: Enable-A and Enable-B of H-Bridge L293D (or L298N)

texts:
I am using both L293D and L298N for controlling the stepper motor NEMA17. It rotates and stop as expected. I am not sure about the usage of Enabling provided by the L293D bridge. In this attached file

the pin 1 and 9 are used to enable. I am currently setting high on both these pin always and the motor rotates. I thought that enabling the pins can be controlled dynamically. For example, can I set low on pin 1, when I am not using the Input 1 and 2? I though this way the pins are not always enabled and reduce the heat in the H-Bridge. Please let me know if that works.


texts:
One of my labs for my computer science hardware organization class has us designing a simple memory circuit. It uses RAM memory with 16 4-bit values. The description is as follows:

"Build a circuit in Logisim that writes the sequence of values 0x0 to 0xf to memory, as shown in Figure 2. The value 0x0 should first be written to the first memory location, then the value 0x1 to the second memory location, and so on. Your circuit should allow the user to reset the counters anytime (via a button). In addition, the circuit should stop writing values to memory after it has already written all memory locations exactly once."

My problem is with the final part, stopping the writing after all locations have been written. My circuit iterates through filling the sports 0x0 to 0xf but then continues and overwrites the current values due to the clock. I have provided a picture of my logisim layout and I was hoping someone could help me fix this.


texts:
I'm trying to design a simple circuit for a 4 LED indicator. Its basically like a game show device that has four buttons. The first one to press their button would have their LED light up and "lock" everyone else out; not allowing the other 3 LEDs to light up.

Below is my attempt at making this circuit with a few AND gates and a few NOT gates. But it doesn't work as needed. It only slightly works by blocking the next LED in line but if the one before it is lit then it turns off. Plus the first LED can always be turned on.

simulate this circuit – Schematic created using CircuitLab

Is there a different component I should be using? Or a different configuration of NOT/AND/OR gates?

All help is appreciated!


texts: Characteristic impedance of a D-subminiature connector

texts:
I would like to know what the characteristic impedance of two adjacent pins of a D-subminiature connector is, or how I can go about calculating it.

For example, see below 50-pin D-sub, if I were to use pins 1 and 2, or 1 and 18, or 2 and 18 - each adjacent to each other - then what would the characteristic/transfer impedance be?

I would like to use two pins for a impedance controlled balanced diff pair and want to know if this connector will pose reflection issues.

It can be calculated using transmission line EM theory but I'm not sure how to include the effect of a grounded connector shield.

I can't find this in MIL-DTL-24308 or any of the manufacturer specs.


texts: Simple Voltage Inverter without using IC

texts:
Say I need to create a negative supply rail of -5V (+-0.5V) from a DC input of +5V without the use of any ICs whatsoever. The components available to me are BJTs, Mosfets, diodes, resistors and caps. So far my basic understanding is this -

Make an oscillator circuit (maybe astable multivibrator) to convert the positive DC into a 0-5V square wave and then use a voltage doubler to get a DC voltage on the negative side.

The problem is that my output is at around -3.5V. Maybe I should amplify the square wave before passing it to the next stage? Or ditch this method altogether? Suggestions would be appreciated.


texts: What does the "OPT" build target stand for?

texts:
When exploring the example projects, I've noticed that the regular Blinky project has 3 targets.

I think I understand what Flash and RAM stand for (it's all a bit confusing), but I haven't seen "OPT" before; what is it? What could it be used for?

I've seen multiple address spaces described for STM32F407 (that I'm using). How does it relate to them?

I think that the assembly file is additionally linked with the OPT target. The parts that interested me were:

;// <e> Flash Option Bytes
FLASH_OPT       EQU     1

and

FLASH_OPTCR    EQU     0x0FFFAAEC
;// </e>

                IF      FLASH_OPT <> 0
                AREA    |.ARM.__AT_0x1FFFC000|, CODE, READONLY
                DCD     FLASH_OPTCR
                ENDIF

                END

I admit I understand close to nothing from them, though.


texts:
I want to make transformer which can convert 220 volt ac to 20-0-20 volt Ac(Step Down) 6 Ampere for audio Amplifier. Now I have a question that For 6 Amp Calculation I should consider 3-0-3 Ampere for or 6 amp on both winding of Secondary or Whole Secondary winding with 6 Amp .

20-0-20 Whole winding 6 amp or I can use 3 amp winding for 0 to 20 and again 3 amp winding for 0 to 20 (20-0-20)


texts:
I would like to use a MOSFET LED Current regulator to source 700mA in 7X Cree XM-L High Power LEDS in series. To test my circuit, i use my workbench powersupply. The image of my circuit is in attaced file
I set voltage at 20V and i use FQPF2N80 as MOSFET Q2 and BC337 as Q1.
But i don't understand, i expected a voltage aroud 0.5V -0.6V at R2, and i obtain only 0.260V? with a current of 330mA? Maybe my input voltage is not enough? Could you help me?
Regards,


texts:
I want to protect sensors that use 3.3V I2C from strong ESD. After searching internet for a while I found that LCO3-3.3 provides protection from 30kV. However, I'm still not sure if the one can be used for protecting 3.3V I/O.

(1) Its max. stand-off voltage is 3.3V, and min. breakdown voltage is 3.3V. Would it mean that 3.31V or 3.32V will be clamped and the I2C communication will be interrupted?

(2) max. clamping voltage is 17V. Then would my 3.3V I2C device be broken by ESD due to the still high voltage after being clamping?

(3) Between uni-direction and bi-directional TVS diode array, which is appropriate for I2C port protection?


texts: What is the purpose of a power MOSFET in this voltage-peak detector?

texts:
I am trying to understand the use of the 3 different power MOSFETS described in this peak-detect circuit. The circuit was designed to measure the voltage peaks from a photomultiplier and the Arduino data-logs and displays the data.
The 3 main circuits from top to bottom are 1. Peak-hold, 2. pulse manipulation, 3. monoflop. My questions concern mainly the peak-hold circuit using the MOSFETs:
Question 1: Since this circuit is low voltage/low current, are power MOSFETs necessary? Why not use transistors NPN transistors or something similar?
Question 2: is the specific choice of IRL3803, IRF4905 and IRL510 important in this circuit? Could these components be swapped with different MOSFETS and achieve the same functionality?
I'm mainly concerned with the use of both IRL and IRF components, since they require 5V and 12V respectively. Is it reasonable to have all IRL components in this circuit?


texts: detect a change in state of voltage divider without using ADC

texts:
I am using a photoresistor for a laser trip wire setup to detect motion.
I am a little short of adc channels here so would like to use a simple GPIO to read the state of the photoresistor ckt.
I am looking for something which will give me a HIGH if laser is tripped and LOW if it isn't.
Any ideas ??


texts: Can I replace a 12a fuse with a 15a fuse on a 12v - 120v automobile inverter?

texts:
I'm hard wiring an inverter into my automobile. Tapping into a 15a fuse in the fuse box. To hard wire it I had to remove the "cigarette plug" and in so doing removed a 12a fuse. I have an inline fuse connector which only takes "bladed" automotive fuses and none of them appear to be 12a, everything I see online for this type of fuse seems to go from 10a to 15a. And I am having a very hard time finding simple 12a inline fuses designed for 12v systems and 12g wire.

So, can I replace the 12a "cigarette lighter" connector fuse with a 15a inline fuse? Or could this endanger the inverter, since it's designed to be protected with a smaller fuse?


texts: Seeing all the transformers around me looks like a huge piece of iron. I was wondering why transformers have such a huge mass. Consider if we need 11V/ 440V voltage transformation. Why don't we have 11 no of turns on primary and 440 turns on the secondary. Theoretically this would give us the required voltage ratios and much less weight. Why doesn't it work? What am I missing?


texts: How can I generate a schematic block diagram image file from verilog?

texts:
I want to create a schematic of a specific verilog module hierarchy showing which blocks are connected to which other blocks.  Much like Novas'/Springsoft's Debussy/Verdi nschema tool, or any of a number of EDA tools that provide a graphical design browser for your RTL.

What tools area available to draw schematics programmatically either from a verilog or vhdl definition, or from some other text-based input format?


texts:
Given the circuit below:

(I simply plan to switch the light bulb on/off and I will later add an optotriac to the gate.)

As I understand, the circuit should work in this configuration, and the light bulb should glow. But it does not. When I connect the live, it flashes a little, and then nothing, I tried more times, it does the same.

The resistor is working, I measured after every try. The triac in off state shows low resistance between gate and MT1, all other pins are unconnected. If I replace the resistor with a jumper wire, the light bulb glows, but all the current flows through the wire from live to gate and from the gate to MT1. I also tried a snubber circuit between MT1 and MT2 (100n 100R) but nothing changed.

What could be the problem? Is my triac blown? Is this a working design at all?

(I used this as the base of my desing: http://www.instructables.com/id/Small-Triac-Switch/)


texts: To-scale images useful for comparing sizes of small (SOT23 and smaller) packages typical for discrete transistors or diodes?

texts:
Is there a to-scale image available somewhere that shows SOT23, SOT323, SOT523, etc. packages used typically for discrete transistors or diodes, so that someone without access to a PCB layout program could compare them?
All I could find is https://www.centralsemi.com/PDFs/literature/Diodes_SF_English_PDF_Version.pdf which is helpful for comparing the larger packages (D2PAK, DPAK, etc.) but not the smaller ones.
(And https://www.mccsemi.com/pdf/SMDDimensionSelectionGuide.pdf where the displayed images are not accurate in relative size)

For example, here is one from ON Semi covering 6-pin packages


texts:
I have one of these inductive sensors marked as PL-08N which should work within a 4-30VDC range and trigger at 8mm or less.

I wired it as described below, with my multimeter probing voltage between sense and GND and my power supplying providing different voltages: 5V, 12V and 24V.

simulate this circuit – Schematic created using CircuitLab

Now to my question: the device seems to trigger properly, with sensitivity increasing with supplied voltage and sense line being pulled correctly to GND, but it does not recover, meaning the LED doesn't turn off and the sense line doesn't go back to VCC once I move the sensor away from the triggering metal plate.

What is wrong?

Using a GM328 transistor tester to test the component this what is reported:

simulate this circuit

I thought about requiring a pull-up resistor on the sense line, but didn't help either...

Is the sensor faulty or what?

UPDATE

It seems the sensor has no trouble recovering from active state if the supply voltage is 5 V turning back inactive once I move the activation plate a couple of mm away fro the activation point, which seems to be at 6-8mm from the sensor surface.
So the question is what makes the sensor latching when supply voltage is relatively high


texts:
I have a 19kHz square wave line-level audio signal (~2Vpp) that I hope to rectify in order to drive an infrared LED at 38kHz.

So far, I've been using a pair of LEDs, wired in parallel in opposite directions, to achieve the same effect, but the resulting system is incredibly sensitive to misalignment and has a very short range (but does work!).

My theory is that if I can rectify the signal in some other way and then drive a single LED, this should eliminate the alignment issues.

Ordinarily, I'd use a standard bridge-rectifier arrangement of diodes, but I'm concerned that the voltage drop may be too high. I've looked for diodes with a low Vf and haven't found much.

What would you use?


texts:
I need to calculate the Link Rate for my GMSL Deserializer which is connected to a 800 * 480 TFT Display.
In that case, I stumbled upon this Article
On the last few lines, they are asking to multiply by 30 for RGB666 and 40 for RGB888.
I am not able to understand this. Why 30 for RGB 666 when 6+6+6 = 18. and same for RGB888.
Even if we including the HSYNC, VSYNC, EN bits, we will not get to 30 in RGB666 format and same for RGB88.
Can someone explain


texts: How to realize a negative voltage with a positive regulated DC output?

texts:
I found an AC adapter that converts 230V 50hz AC to +16V, 0V, 32V (3 pins) DC.  I wanted to convert this into a +12V, -12V dual power supply. Someone suggested that I use a positive buck converter to create the +12V but he told me that I would not be able to create a -12V by just using the same technique; a buck for 32V and connect the terminals in reverse for -12V
I didn't get why this is true.

simulate this circuit – Schematic created using CircuitLab
Physically, if I have two 1 V batteries, how should I connect the second battery to get a -1V at node 2. Afaik I would just flip the terminals of the second battery like circuit A, but how is this any different from circuit B? Is circuit A even right? Else how would I get a negative voltage with a +1V battery at node 2? In other words, practically, how would I ensure a ground in the middle?
Here's the nameplate of the AC Adapter: https://imgur.com/a/K1VXz8X
Edit: I replaced the transistor with a box with 2 nodes, node 1 requires +1V and node 2 requires -1V


texts:
I am trying to send something from an atmega to my pc.
The setup is: Ubuntu 14.04, atmega644P-20PU, USBASP v2, TTL-to-USB pl2303
Firstly I tried to write the code in C and used this code  and then this one and I got the same result: '�' or random characters (in minicom or screen)
Then I gave up the C and uploaded a simple Arduino program:
void setup()
{
   Serial.begin(9600);
}
void loop()
{
   delay(500);
   Serial.write('t');
}

(when running arduino I put a 16MHz crystal. in other cases I used a 20Mhz one. Also setting F_CPU accordingly in the code.)
In all the cases the R(receive) LED of the pl2303 is blinking at the right moments (depending on the delay set in code).
Also I used CuteCom to view what I am getting from the serial port and instead of '�', depending on the code used I get "\0x00\0x80\0x80" (for Arduino code) or in other cases "\0x80\0x00\0x80".
I use RX0 and TX0 (pin 14 and 15).
RX0 connected to TX of pl2303 and RX of pl2303 to TX0 of the mcu.
I also shorted RX and TX of pl2303 and tried to send data across it and I receive back what I send.
Baud rate of pl2303 is 9600

$stty -F /dev/ttyUSB1
speed 9600 baud; line = 0;
min = 60; time = 1;
ignbrk -brkint -icrnl -imaxbel
-opost -onlcr
-isig -icanon -iexten -echo -echoe -echok -echoctl -echoke

In all cases I used 8N1.
I hope I was specific enough and coherent.
(normally I try to find myself answers and solutions, but now I'm lost)


texts: For my power-supply micro-controller is a load. How does this load behave like? is it resistive or capacitive or inductive load?


texts: How is the memory space calculated as 64KB for this MCU memory?

texts:
When it is about an 16 bit microcontroller with 16-bit adress 0xFFFF(the largest 16-bit number is 0xFFFF in hex or 65535 in decimal) the following picture is given and total memory space is given as 64KB:

I take 1 byte as 8 bits. Above the blue is my calculation of the memory space. I calculate it as 128KB but it is given as 64KB. Where am I wrong?


texts:
I am designing a circuit with USB 3.0, and looking at the reference design from Cypress in the link below.

SuperSpeed Explorer Kit User Guide (CYUSB3KIT-003)

I see on page 47., that the USB connector shield is connected to system ground using a LC circuit, consisting of a 100nF capacitor and a 220ohm Ferritbead.

EMIFILr (Inductor type) Chip Ferrite Bead BLM21P Series (0805 Size)

At DC the ferritbead allows current to flow, and at 100MHz it has a resistance of 220ohm.
At only 1MHz the capacitor has an impedance of around 1.6ohm, which is almost a short.

I cannot understand the purpose of the ferritbead ?