# All Questions

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31 views

### Switching ON/OFF an ADC line

which electronic component could one use to switch ON/OFF several external lines for ADC? Context: I am working on a small project where I would like to measure 4 external voltages (0-3V range, let's ...
• 101
46 views

### Dual edge triggered Bistable Multivibrator [closed]

Design a bistable multivibrator to increase the frequency at which the data is stored. When doing so, ensure that the data is stored at the rising and falling edge of the clock. However, due to lack ...
1k views

### Why is the MOSFET in this fan control circuit overheating?

I’ve designed a fan control circuit using an N-channel MOSFET (STN3NF06L.) The fan operates at 12V, and I’ve isolated the 12V side from the 3.3V microcontroller side using an optocoupler (ACPL-W314-...
40 views

### 3-Phase system Voltage conversion

If we are converting from Y to delta configuration or vice-versa, how do we convert the phases of our voltages? I've seen that we need to add or subtract 30 degrees from one another, but I don't ...
97 views

### IR Blaster Resistor Calculation for IR LED (breaking ohm's law?)

We are trying to build IR Blaster based on schematics provided by Tuya. I believe Tuya based IR blasters sells hundred of thousands per month if not millions. So I am quite sure that their schematics ...
• 55
959 views

### What is the function of this resistor and capacitor at the input of optoisolator?

This "equivalent input circuit" shows a resistor and capacitor at the input of optoisolator (inside the red oval): Are they used just for modelling, or there are actual physical components ...
• 472
105 views

### Trying to identify this chip and possibly its functionality?

I applied too much voltage to my Smooth Stepper and I'm just trying to learn a little about it and possibly get lucky and fix it. I'm trying to identify the IC in the picture, as I believe this took ...
13 views

### Can I use a large ESC controller with a mini BLDC motor? [closed]

I bought a HappyModel SE0802 19000KV Brushless motor for a project. I have a 30A 2S-4S BLHeli ESC controller. Is it possible to run the motor with this ESC controller?
1 vote
42 views

### ESD protection device selection

I want to select a ESD protection IC for my circuit with the following conditions: Battery based and ultra-low-power Battery voltage 3.6 V My sensitive chips inside my circuit has Absolute Maximum ...
• 547
38 views

### What are the VDDSD, VLXSD, and VFBSD pins?

On the STM32WB09KEV, and on MCUs in general, what do the VDDSD, VLXSD, and VFBSD pins mean. I can see that they have something to do with SMPS (input/output, ground and output), but what do they ...
74 views

### Replacing the BJT in the current limiting circuit with a MOSFET

I was looking for a current limiting circuit and found an implementation using TL431 and a bipolar transistor. However, I did not have a bipolar transistor at hand for the required current and ...
49 views

### Verifying if HSE is used by MCU as system clock without probing

I have a PCB where I use an 8 MHz quartz resonator as this MCU's external system clock source. In STM32CubeIDE the setting is as follows: The program runs fine in MCU, but I cannot be sure if HSE is ...
• 2,217
15 views

### plecs simulation of output impedance of switched capacitor(SC) converters

I am trying to simulate how output impedance of several DC/DC switched capacitor converters(dickson, ladder, and series-parallel) changes as switching frequency increases. I referred to several papers;...
1 vote
59 views

### How to simulate for the Gain of opamp Bridge Differential Amplifier?

Hi experts, I have this circuit, with a bridge connected to an op-amp in differential form, and I want to simulate it for the Gain of the circuit in PSPICE. I have found it's gain by hand, which comes ...
1 vote
41 views

### Ebers Moll parameters for MPSA18 and AC128 BJT transistors

First of all, I should mention electronics is not my field so my problem might be trivial for you. I'm currently working on my thesis and I need to model two BJT transistors: NPN MPSA18 and PNP AC128. ...
32 views

### I2C Write Function and Making the Array User Inputtable with Python

I'm wrapping up the firmware for my project using 4 TCA9548As to switch between 32 different ports for I2C slave devices. I have a raspberry pi and clamp on master SDA and SCL lines for master input. ...
18 views

### How to connect several sheet symbols with [x...y] stye ports to a bus?

I have two ADC units within my hierarchical design. Each ADC unit have 16 inputs which I made with ADC[0..15] sheet port. Is it even possible to use both units? Now ...
• 3,012
57 views

### Replacing USB-C socket on a keyboard

I decided to fix some of my stuff that has broken USB-C ports. (why are they so fragile!) I've removed the old sockets and cleaned the pads, but when the old sockets were damaged (by simply inserting ...
24 views

### Troubleshooting of Emerson Jacking Soft Starter [closed]

The Soft starter is tripping and showing motor connection immediately it is put to run. I have checked the motor connection and the power connections on the control system but the error is still ...
1 vote
77 views

### Filter on SEPIC architecture output for making +/- 60 V from 11 V input

I'm working on a LM5155 Boost/Flyback/SEPIC controller reference design PMP40488 from TI. The goal of the design is making variable output (maximum +/- 60 V) from 11 V input. My question is related to ...
• 547
1 vote
29 views

### Cannot decode IR signals using IRRemote Library

I'm using RC5 encoding for my project. I'm sending signals using RC5 Protocol. The transmitter is sending the signals correctly. But on the receiver node, when I decode the signals, Library is unable ...
1 vote
51 views

### Debugger/Programmer Invalid Target Device

I use a PicKit5 to program a PIC24EP128MC202 using MPLAB x IDE v6.20 with XC16 Compiler, I recently fixed some memory model issues and I ran into this problem where "Invalid Target Device" ...
67 views

### Nanogrid management PCB review

I have made some progress on the PCB for a nanogrid consisting of solar panel, wind turbine, batteries, load (not yet connected) this board monitors the current/voltage of each components and sends ...
1 vote
50 views

### STM32 MCU doesn't reset after flash

I'm using STM32CubeProgrammer to flash an MCU. But after flash completes, to reset and run the MCU I have to interact with NRST pin by a push button. Is there a way that right after the flash the MCU ...
• 2,217
87 views

### What is the role for each of these AC coupling components?

I'd like to learn more about the RP2040 PWM Audio AC coupling circuit found in figure 22 in this document. Figure 22. Schematic section showing the Analogue PWM audio circuit Even though I understand ...
• 101
1 vote
69 views

### Why does this push-pull converter fail?

Consider the following circuit of a push-pull converter. I would be interested to learn why you think it fails (MOSFET and controller). The controller is a UCC28084. The MOSFETs are SSM3K361R (i.e. ...
• 22.5k
1 vote
30 views

### PIC24 memory model problem error

I attempted to run a code to start understanding how PIC24 works but I run into a memory model problem. I don't understand what's his optimization issue since I have enough space to write it on, and ...
83 views

### Constant output voltage in buck-boost converters

I'm a self-taught student. I'm trying to understand the working principle of buck-boost converters in continuous conduction mode. When the switch is turned on, the equation describing the inductor is ...
• 311
38 views

1 vote
42 views

### Is there a simple approximation for B-field strength of a loop antenna when driven at 10 GHz?

I have a near-field loop antenna that I'm applying a microwave field to at 10 GHz. I'd like to have it interact with a small magnet that is much smaller than the loop. Here's a picture with the little ...
51 views

### Audio Codec Input/Output Channel Stages

I am planning to build a PCB for a Eurorack Modular Synthesizer, incorporating an STM32 for DSP and a bidirectional Audio Codec like the TLV320AIC3104 to handle the ADC/DAC. Eurorack audio signals ...
745 views

### How to connect to "upstands" on the PCB without soldering?

I've got two items of the same model number, but one of them has a Phoenix type terminal on the PCB for the connection. See photo below. The other one has "upstands" poking out of the PCB. ...
• 601
58 views

### 4N25 Optocoupler design

Below is a simple 4N25 optocoupler circuit that I designed in LTspice. 10 mA is flowing through the input. It works in saturation. According to the datasheet in Figure 2 (CTR-sat), it says 0.7, so the ...
• 385
56 views

### Active Bandpass with "Tunable" F Using Potentiometer

I'm trying to construct a simple bandpass filter circuit using the multiple feedback topology with one op-amp (I'd like to leave out a dual-opamp approach for now). I'd like the center frequency to be ...
• 103
30 views

### Part number of this IC marking "R2. 8"

Can anyone please help me define the part number of this part marking "R2. 8" in the picture below?
41 views

### Accumulate load time and retain through a power cut?

I have a question around closing a relay after a load been active for a specific elapsed time; and the time is always known even through a total power cut; ideally din rail components would be able to ...
32 views

### EAGLECAD Create a device with one mulit-instance package

I need to create some switches as devices. The switches consists, from the PCB-side of view, only of a bunch of ST2,8 connectors. These are based on the connectors within the existing con-rib.lib. To ...
59 views

### Non contact AC voltage detector circuit current calculation

This seems to be a common circuit for a non-contact AC voltage detector: Non-Contact AC Line Detector using BC547 The probe generates a small amount of current when it is near an AC line due to ...
65 views

### Multimeter fuse [closed]

Hello guys my multimeter has no fuse or no fuse to put into it where can i put my fuse ?
1 vote
47 views

### What's the deal with this comparator's hysteresis?

I have here a circuit designed by someone else to create a 50% duty cycle square wave that leads a current transformer in phase. The CT maxes out at about 1 amp, and the output of the phase-leading ...
37 views

### ICs for Low Voltage Analog to Digital Conversion [closed]

I'm looking for an ADC IC that works in very low voltage ranges (0 - 50mV), and with a resolution of at least 1024 steps. I was wondering if anyone knew if this sort of device even existed, or what a ...
31 views

### How do I decompose 6 or more variable truth table to groups of 4 or 3 variable truth table and K-map them and combine the equations?

K-maps are a go to method of finding SOP/POS form for truth tables of up to 4 variables, beyond that the K-maps become explosively complex to manually draw and solve. Is it possible that for 6 bit ...
• 565
179 views

### How do I light an LED on a ground signal when I don't have enough voltage left after the PNP?

I am working with a circuit that grounds when a LED is to turn on. I have an 8V supply voltage for the LED, which cannot exceed 10mA. The signal to turn on the light is a very weak 6.5V, so Vbe is ...
• 2,150
56 views

### Injecting bits to a parallel communication bus possible?

Antennas can recieve data (bits) because RF signals induce an analog signal into it in a serial format, essentially a voltage that varies over time. My question is can we have an antenna that can ...
• 15
30 views

### Analog pulse width detection [closed]

I have to make an analog circuit that the input is a pwm, when the pulse width is 1000ms the output must be 0 and when the pulse width is 750ms the output must be 1, i tried using an 555 with a ...
36 views

### Can a voltage higher than LED maximum be used when using constant-current LED driver?

I am planning to use these components: TLC59283 CREE J Series 5630 LEDs Specifically, I want to create a setup like Figure 9-1 on pg. 22 of the TLC59283 datasheet. Currently, I am trying to choose a ...
• 303
63 views

### Confusion with two types of differential signal coupling

I'm having difficulty to articulate the question. But perhaps I might get close to it by an example. I know that in differential signaling, both the signal and the receiving amplifier can be in ...
• 4,333
64 views

### How can i make this idea work in PCB?

Assume i have a source of energy (voltage source), i want to sense the voltage and current of this source and transfer this analog information to an ADC (arduino nano) thus i have to make the voltage/...
1 vote
87 views

### Is the x-capacitor essential in the circuit below?

hi I hear a buzzing noise from c1 and L1 in this circuit C1 used a film capacitor, not an X capacitor (Film capacitors were used instead of x capacitors because of internal space problems.) I thought ...