# All Questions

114,233 questions
29 views

### Unit Gain Op amps not working LM2904p

I am trying to use the LM2904P as a voltage buffer. i am using a volt meter at the output, and i get 10v when it should be 2v. This is pretty much what my setup is. - is In1- and + is In1+. i dont ...
33 views

### Best way to crimping the outer tabs of a Crimp Terminal Contact

I'm trying to find the best way to crimp the JST VH series crimp terminal contact I'm using my Knippex tool to perform the crimp Now I always get good results with the inner tabs, but the outer tabs ...
30 views

### Using analog hall effect sensor with a non-inverting schmitt trigger

I have an analog hall effect sensor (i.e. UGN3503UA) that I want to convert to digital by using a non-inverting schmitt trigger. The issue I am facing is that when I connect the output of the hall ...
41 views

### simulate a motor with resistor and inductor

I want to simulate a motor with a resistor and inductor. It means I want to connect a resistor and inductor to 1-phase or 3-phase instead of a motor. For achieving this goal I have to measure both ...
90 views

### multimeter temperature accuracy

I have tried searching for an answer and looked online, but I'm just getting more confused. I have a DMM that measures temperature with a thermocouple lead, with a resolution of 1 degree C (shows 020)...
30 views

### Connecting an Arduino to Raspberry Pi

I'm trying to connect an arduino with 3 sg92r servo motors on it and an RPI with and lcd and the serial of the arduino connected to it. They are both connected to a power supply with 9v/1A and 5v/2....
98 views

### Why do you use a buffer when the whole point of op amp is to amplify signal?

This might sound like a dumb question but I just learned about buffers and learned that they have same Vin and Vout from the amplifier providing nearly identical Voltage source value to the next op ...
45 views

### Electrical circuit design questions

So I was wondering if there is any site or papers that has fun electrical circuit questions, such as placing the right components on a circuit to make it work, make the light dimmer/brighter by using ...
6 views

### Can I configure pairing for HC-05 and Arduino, and use the HC-05 without Arduino after? [migrated]

I have a system that is outputting data via its serial, and I need to relay that data to my PC wireless-ly. If I were to setup an Arduino and HC-05 at the system's side to relay the data, that would ...
35 views

### Hold-time Violation and timing diagrams

I was wondering what the output of capturing flop looks like, if there is a hold time violation from capture flop. Can anyone explain with a timing diagram?
55 views

### Triggering buttons on a remote with a Raspberry Pi

I would like to control my AC with a Raspberry Pi. My system is similar to this one, although it is an older model from 2004. Currently the system has a wired controller. There is no bluetooth, wifi, ...
40 views

### Zero-R Resistor on XTAL pins

Looking at the schematics of the STM32F4-Discovery board page 28, whose screenshot is attached below.. there is a Zero Ohms resistor 'R25' which is shown in the circuit with the Crystal. And there is ...
23 views

### Strange powerplane layering issue in designspark

I'm trying to order a 6 layer PCB from a fab but they are asking me to resolve an issue with the file and I'm a bit stumped on what to do about it. The second layer of the design I have designated as ...
20 views

### Signal Attenuation TVS and series resistor

This question is in regards to signal attenuation on high speed data lines like RS-485 (and any others as well). I'm new to the signal world, so please bear with me here. Are there some useful ...
79 views

### Why is my radio circuit not functioning correctly?

Ive built this circuit and it hasnt functioned correctly it picks up a humming which im pretty sure it is my power supply Can someone explain why this isnt operating as a radio? and maybe assist me ...
1k views

### Does anybody know what this IC is?

I tried different search keywords combinations, but I couldn’t find a datasheet, nor a hint of what this IC could be. Maybe someone who’s familiar with it could give me a clue. The IC is on a board ...
12 views

### How to calculate or show in matlab/pspice the DC component from a circuit simulation?

Based on Pspice I'm simulating this RL full wave rectifier That gives the next voltage and current output at the showed probe point The idea is to extract the DC component of the current or voltage, ...
14 views

### Proteus-How do I connect 5 inputs to get 4 outputs with a dipswitch?

I'm having trouble with making a schematic; I have 5 inputs and 4 outputs (dipswitch and 4 leds) basically depends on the first input (then on the other 2 inputs) which led is going to turn on. The ...
21 views

### Soldering Iron and Electrostatic Bracelet Connection

I have a DIY soldering station and I want to ground the soldering iron and I also want to use a electrostatic bracelet connector for the soldering station. Can you please help me how to connect the ...
18 views

### NRF24L01+ transmission problem

I'm trying to make the modules work on 2 arduino nanos but it just doesn't work.The serial monitor just prints random symbols instead of the "Hello".I tried everything I could find on the internet but ...
26 views

### link dot matrix LEDs with tiny dc electro motor [on hold]

I wanna link every single dot matrix LEDs with tiny dc electro motor can you guide me how should I do that ? have any one done that before ? thank you all
38 views

### Shield grounding location for an STP cable in a balanced system

If a balanced source or driver is coupled to a differential balanced receiver via a balanced STP cable as shown in the hand drawn illustration below: in such case I have read that grounding the ...
25 views

### 3s lipo battery 11.1 volts for rc planes [on hold]

I recently bought a 3s 11.1 volt lipo battery and a charger and a voltage tester, now when i plug the battery to the voltage tester its showing "2cs", and on the balance charger 2nd led is green , 1st ...
29 views

### Mosfet Gate-Source Zener

I want to confirm this circuit is going to work and ask how to calculate the zener voltage. The load is going to be driven by 30 volts, and the gate voltage is the same 30v, through an optocoupler.
15 views

### Hexagonal hatched polygons Altium

I'm recently trying to design a flex PCB. I haven't been able to find any specific tutorials on how to do this in Altium. But I did find Altium blogs detailing some of the best design practices for ...
22 views

### AVR DMX Transmitter outputs constant squarewave, not the form of a DMX packet

I'm using an ATMEGA328, with an external 20MHz crystal and fuses set by avrdude as -U lfuse:w:0x46:m -U hfuse:w:0xdf:m. I want to send DMX with it. Using the code ...
25 views

### R_on for inverter gate

What $R_{on}$ do I use to calculate the delay for an inverter gate? In my class we came up with two definitions of $R_{on}$, one for saturation and one for triode. Is there a certain mode I ...
29 views

### Circuit protection problem driving high side MOSFET continuously

I need to drive a high side N-channel MOSFET continuously. The circuit is essentially a passthrough, and the only thing I want to do is turn this pass through line on or off (usually if not always on)...
78 views

I am using the NRF52832 and code it with arduino. I am reading A0 to get a signal from a sensor at 1m cable length. simulate this circuit – Schematic created using CircuitLab If I disconnect ...
36 views

### Common ground on a switch mode power supply

I've got a switch mode power supply and I have a question on the grounding of the PCB. Documentation on the PSU can be found here: https://docs-emea.rs-online.com/webdocs/1621/0900766b81621ef9.pdf ...
29 views

### Feedback signal consumed in VHDL

Hello I'm new with VHDL and I'm trying to implement a JK latch in VHDL using this RTL schema: Where the "latch_rs" is written as follow: ...
30 views

### Switch ON/OFF in MAX1709

I am designing a project where I'm going to use the MAX1709 step-up converter. There is a possibility to switch the converter ON/OFF with the help of ONA/ONB inputs, but according to schematic in the ...
47 views

### Noise quantification from sampled data

If a sampled voltage signal $y[n]$ is composed of its offset $\bar y$ plus noise $x[n]$; i.e. $y[n] = \bar y + x[n]$, are both following equations for the RMS value of the noise component \\$\...
48 views

### High SNR FM demodulation

So I need to demodulate the FM signal from a sensor with highest SNR possible, at least 70-75 dB. IF is 10.7 MHz, max. deviation is 200 kHz but I can change those values if needed. Baseband signal ...
61 views

### PWM with ADC - ATMega16

I want to write code where I move the wiper of the potentiometer clockwise so it applies PWM on a pin, and when I move it counter-clockwise it applies PWM on another pin. I could do it with Arduino, ...
40 views

### Sideband Production

I am trying to understand exactly how sidebands are made. I've seen the math, but I'm looking for more of a component-level understanding of how they are made and what properties of the mixer ...
68 views

### P-MOSFET failures

simulate this circuit – Schematic created using CircuitLab P-Mosfet Datasheet The goal is that 5V (or logic high) appears on U3 when there is logic low on U4 and logic high on U2. That 0V (or ...
25 views

### Combining two led strips with separate controllers

Out of practice and have forgotten basic principles but would like to combine two led strips to one controller so they operate in sync. Have combined output from sensor into control box but outputs ...
37 views

### Connecting two wires to a DC 12v port on a controller board with 4 pads for a monitor

Sorry, the question was difficult to word. Basically I recently bought a controller board for a monitor and the DC cable I got wasn't correct. So until I get the right part, I just want to test the ...
26 views

### How to connect a MEMS Microphone Breakout - INMP401 to a RN-52 bluetooth module?

I intended to use a INMP401 (MEMS MIC) to capture audio and stream it via bluetooth using an RN-52 bluetooth module (RN-52). The RN-52 has inputs for differential +- signals. The INMP outputs ...
48 views

### Large dynamic range current sense 1uA - 100mA

I am looking at large dynamic circuits and came across an interesting project by ETH Zurich called the rocket logger - https://rocketlogger.ethz.ch/ I am a little confused by their current sensing ...
38 views

### Design ethernet switch for multiple devices on pcb?

I'm working on a pcb design with a Raspberry Pi CM module and a microcontroller with ethernet capacity. The goal is to connect the devices to the internet. I'm currently using a normal ethernet ...
52 views

### Charge a 12V marine/boat battery with AC

need to build a diode bridge to recharge a battery (car/boat type) from a boat engine that gives 12V AC. I thought of doing something like this: simulate this circuit – Schematic created using ...
43 views

### What's the actual cause of unbalanced combinational logic?

So far when I find timing issues, I try to pipeline combinational logic. It always works. Today, my Quartus Compilation Report show up -ve slack values. I double check it with TimeQuest Timing ...
38 views

### +/-10v Op-amp output with DAC

I'm using the OPA227 configured as a differential amplifier to generate a +/-10v signal from a DAC. In the diagram above, VREF = 2.048, and DACOUT swings between 0 - 4.096. The resistors values give ...
14 views

### RN4871 auto pairing

We are developing an application which needs the BLE Peripheral to be automatically paired with the smartphone when the smartphone is near the BLE Peripheral. We are using RN4871 Microchip BLE Board. ...
35 views

### Simplifying logic circuit

I've been trying to simplify a combinational circuit and wanted to know whether there was any simpler way of solving such questions. Do we have to find all the outputs and such or we can use a simpler ...
25 views

### MQTT Broker vs Server

I am trying to learn MQTT technology. What I understand so far, is that MQTT is based on a 'Broker' that does the 'Publish and Subscribe' of messages and topics. I wonder if it's another name for '...