All Questions

114,519 questions
143 views

Error handling in embedded systems development

I am developing a Firmware and I am using 3 layers: Driver, Platform and Application. In order to handle the communication between these layers, I am using an approach where each function will return ...
97 views

RS485 vs RS232 similarity vs differences

I have used UART RS232 communication between MCUs extensively. Now I need to interface my STM32F407 MCU over RS485 bus with with devices. I have understood few things about RS485 but not-clear about ...
26 views

Altium can't remove extruded mechanical layer in 3D view

I'm using Altium designer 18, and "suddenly" while designing all these gray shapes appeared. After trying to restart Altium they were still there. Closer inspection showed these pads are exactly where ...
23 views

how do i send notice board notification to a wireless bluetooth hardware and then to a android smartphone using bluetooth [on hold]

i want to send notice board message(this i will be uploading through a website ) to a Bluetooth hardware (wireless) and then get the same message on my android smartphone when i pair the device with ...
78 views

Why is my 180v dc motor circuit not working?

I bought a "Johnson" treadmill motor that I know works well, it's 180v, 10amp, 2.5hp. I decided to go with the cheap setup, so I powered it through a 10000w 80amp max scr, going through a full bridge ...
52 views

analog IR sensor [on hold]

I am using this analog IR sensor circuit. Output varies greatly in different place and different light. Can you suggest how to modify this circuit so that output is stable? Shadow, light from ...
44 views

Long range, medium speed RF data transmission? [on hold]

I'd like to stream an audio signal, roughly real-time, with a data rate of at least 256kbps. The RF link should be bidirectional to allow for control signals, however if necessary it may be heavily ...
515 views

Why is the collector current I_c for a normal common emitter BJT circuit LARGER than that of the Darlington transistor circuit configuration?

I'm a noob to electronics and have been reading up on transistors. I tried to simulate Darlington (NPN) and Sziklai transistor and compare them against a single common emitter NPN configuration, ...
30 views

RC integrator+ BJT emitter follower

i am designing a circuit able to draw IV curves of LEDS and diodes through Arduino. Basically i use the PWM function and an RC integrator to have an approximately constant voltage. Then i would ...
30 views

Can laptop be damaged from electric shock and it's charger remain working? [on hold]

I've bought an ACER laptop, which stopped working after a week. I've checked the charger and it's giving me steady 19.5V. I returned it to the service since it's brand new, and after 2 days they said ...
25 views

ERC error EAGLE

I do not understand why I am getting and error for the POWER pin IC2 and IC3, I have attached Vcc+ to + and Vcc- to -. What am I doing wrong?
18 views

ADC sensing Range of MSP430I2020 controller

my project is based on Weight scaling using load cell. currently, I'm working on inbuilt 24 bit ADC of msp430i2020 controller.internal ADC reference voltage is 1.2 volt. Capacity of load cell -300KG ...
36 views

Bitstream autocorrelation? - comparing two bitstreams - BER?

I am sending a PN9 sequence from a sender to a receiver and want to compare the received bitstream (RB) to the sent one (SB). I am assuming that the transmission will get distorted and want to somehow ...
105 views

±12V protection for MIDI output

TLDR; how to make a MIDI output withstand shorting it to $\pm12$V? I'm designing a MIDI output in a eurorack modular synth module on a TRS jack (this is a semi-standard non-standard way to save ...
26 views

Arduino Due non-standard Clock Output [on hold]

I have Arduino Due, and I want it to output clock at 3.072MHz (which is a clock rate used for I2S) How do I go about this? I tried the following code, but it doesn't give the exact rate, and I ...
107 views

“AC socket” that solders directly on PCB [on hold]

I'm developing a device that is intended to be put between the wall socket and the device itself. The idea is to have a format similar to this figure: https://img-static.insania.com/imagens/50000/...
45 views

Does potentiometer accuracy change with degree of movement?

I want to use a conductive plastic potentiometer for my actuator application where movement is +/- 40 degrees. As in datasheet, the potentiometer linearity is given as +/-0.2 % which I think is for ...
77 views

Weird FET results for noob

Wisdom states that the load is connected to the drain, and the source connected to pos or 0v dependant on P or N channel. However ... I have a "2N3820" (a p-channel in TO92 package), so pin out (...
116 views

What type of terminal is this

Okay, simple yet seemingly impossible question here... What type of terminal is this? It looks like exactly what we need, but I found the image on an advert for the shrink-wrap shown in the picture. ...
37 views

Use of internal PCB ground plane as ESD baseplate/EMC reference plane of product in plastic enclosure

I am designing an electronic product which will be housed in a plastic (non-conductive) enclosure. There are a number of, mostly shielded, I/O cables (Copper 10/100/1000Mb/s Ethernet, USB 2.0, RS232, ...
57 views

220v to 5v AC to DC Rectifier IC [on hold]

I am working on a small project where I need to convert 220v AC to 5v DC with at least 100mA current. I am currently using Hi-Link's converter to achieve the goal and it's working great. I am looking ...
28 views

Sensorless speed control and startup of BLDC

Regarding the sensorless speed control of a BLDC, I have some doubt about what may happen in two scenarios when the rotor's position is unknown: 1) the start-up from zero and 2) with an initial ...
42 views

Creating a temperature-dependent solar cell in LTSpice (using varistors)

I'm currently working on my master thesis and therefore need to simulate a solar cell in LTSpice. I've already modeled and simulated some examples with constant values. But for a more accurate model, ...
119 views

Reducing noise in this audio amplifier

Here is a picture of a circuit I built. I'm a novice in building amplifiers, but I'm interested in building a simple circuit that picks up music using a condenser microphone and transmits it across ...
27 views

Noise immunity and noise margin

Why is noise margin in logic gates a quantitative measure of noise immunity? Can anyone provide an instantiation to demonstrate how noise margin is a measure of noise immunity
10 views

PSoC 4 interface configurations

Is it possible to use the PSoc4 module with configuring three different interfaces? The problem is that i have three different sensors and need to connect all of them to the PSoC.
22 views

Multimode to singlemode optic fiber

I'm naive in this field, but I will need to use optic fibers for optogenetics application. I already know that my question will sound stupid for the most of you, please forgive me for that. My ...
71 views

What is the fastest SiC MOSFET?

I would like to know what is the fastest SiC FET greater than or equal to 10A in a TO-247-3 package. Currently I am using a C2M0280120D. My switching speed is 7 MHz. I want to know if there is a ...
26 views

DALI optical isolation of signal, but no power isolation?

The DALI standard suggests a separated power supply, because the DALI control lines are not galvanically isolated, so mains voltage may appear on the lines (and the standard suggests that DALI devices ...
44 views

MCP73871 Battery Under Voltage Protection

I want to use MCP73871. Is there a battery under voltage protection in this charger IC? or may I use a battery protection IC? Answer for @Bimpelrekkie I decide to use my power architecture as ...
20 views

LPC1768 Clock Out pin

In the LPC1768 User manual, it is written P1.27 2nd function is CLKOUT. But in the keil debugger it is written reserved. When I checked clock out pin after enabling, I only get 0 V.
1k views

Why don't the fuse connections in programmable ROM cause the whole matrix to be shorted together?

If the rationale of using diodes in ROM (rather than simple wires) is to prevent the matrix being shorted together, then why does shorting not occur for programmable ROM - which has blowable fuse ...
47 views

Clarity on dB SPL calculation

Based on this post, let me assume that I have a input source of 94 dB SPL / 1 Pa that a microphone is picking sounds from. The microphone has a sensitivity of -46dBV/Pa , this gives 0.005012 V RMS/ ...
39 views

Sensors with CAN Communication [on hold]

Can anybody refer a sensor (or an Energy meter) which is having CAN Communication protocol? I would like to test the CAN communication using my CAN-USB Protocol analyzer. Thanks in advance.
24 views

Choosing a position sensor (encoder) and obtaining velocity from it

How do I know how many counts per revolution I need for an encoder for my application? I need to be able to accurately capture a 1000 Hz signal on an input side running from 1-133 rev/sec (60-8000 ...
37 views

Changing the Linux SDK in the embedded platform [on hold]

I am using an embedded platform that has Linux SDK version 2. It supports only gcc 4.9.2. Is it possible to configure the system to run gcc 8?
111 views

I2C Issues with First PCB

As a forewarning, this is my first PCB. I am experiencing issues with the I2C bus. There are two I2C slaves on this bus (SSD1306 display and BQ27441 Fuel gauge, currently the program only sends ...
71 views

Cause of high failure rate in SC189 buck regulator

I have a small board that uses the SC189C buck regulator to take 5 V down to 3.3 V. For whatever reason somewhere between 25% and 50% of these boards have had the voltage regulator fail at some point, ...
14 views

Why Backwards field rotor current are higer and of lower pf?

I have read a book in which it is written that backwards fields rotor current are higher and have lower power factor and low slip. But at low slip resistance is high as compared to forward field so ...
42 views

How to operate 1602 LCD on 3.3V [on hold]

I wonder if its possible to run a common 16x2 LCD with 3.3v power supply. Its datasheet shows supply voltage = 5V. Are there any 3.3V variants of 16x2 LCD modules?
85 views

How to detect a partial discharge in a noisy signal?

I am working on a competition where we are required to detect partial discharges in given signals. Each signal represents a measurement of some power-line voltage. I know that partial discharges ...
79 views

High current, low voltage capacitors

I'm putting together a high current (200A+), low voltage (<5v) rectifier circuit. I have sufficient bridge rectifiers, but to smooth out the waveform I need a strong enough capacitor bank. Besides ...
23 views

The relay controller circuit in a pre-amp stopped working properly

I have a pre-amp with a controller circuit which controls input signal micro-relays and a power supply relay. While the input signal micro-relays work normally, all of a sudden the 30 second delay for ...
60 views

LTC3106 - getting 3.26v instead of 3.3v

We designed a power supply for an iOT. The uses SoCl2 battery and solar panel combination. The circuit is functioning and we are getting 3.26v consistently for over 3 days now. LTC3106 is configured ...
55 views

What exact connector is this?

I'm trying figure out what connector this is? The pitch is 2mm. I believe it may be a type of JST connector. connector: mate: pitch:
65 views

When (not why) do I need a pull down resistor?

I am trying to control an old 6510 (yes, the C64 processor) with an arduino mega. I am having troubles reading the address line and I wonder if that's because my connection between the arduino pins ...
126 views

I'm working in an office with a Wi-Fi router, desktop, and a few cell phones making RF noise. I have an 8 feet long by a 3-feet wide table, and I have an Aaronia BICOLOG 30100 + spectrum analyzer + ...
16 views

ENC28J60 - is this connection correct

Just wondering if this is correct. I never used to design anything using this chip.