Skip to main content

Questions tagged [opto-isolator]

An optoelectronic device which combines an optical transmitter and receiver in a single package; commonly used in galvanic-isolated control applications such as power supplies.

Filter by
Sorted by
Tagged with
0 votes
1 answer
53 views

TLP292 Schematic Review

I am designing a circuit with TLP292. Below is the schematic. The I/P is coming from a microcontroller it is either 0 V or 5 V. The output current is 15mA to 20mA May I know is this circuit is fine? ...
Confused's user avatar
  • 2,338
23 votes
3 answers
2k views

What is "Arduino Optocoupler Disease"?

Another post on this site, when critiquing a pcb design, referred to "Arduino optocoupler disease" spreading across the internet. What type of design mistake does this refer to?
Chuu's user avatar
  • 339
0 votes
1 answer
35 views

ESP32: Detect switch or button state / GPIO to GND vs GPIO to 3.3V

I want to detect a binary switch state - better said a logic 1 or 0 via a PC817 optocoupler - and my question is, if both of these ways are correct: A) Connecting the GPIO input pin via the ...
Tintenfisch's user avatar
0 votes
1 answer
72 views

How to read the output of a slot-type photomicrosensor with a MCU?

I am trying to use an optocoupler as an edge sensor (to restrict motion). I am using these ones: https://www.aliexpress.com/item/1005001921249243.html Or same diagram here: https://assets.omron.eu/...
LRDPRDX's user avatar
  • 163
0 votes
0 answers
23 views

ESP32 rebooting on gpio LOW

I am using esp32-wroom-32 module to turn on/off the 24v electronic solenoid valve using 5v relay. Detailed circuit is shown in the image below. However according to my observation whenever the ...
java bee's user avatar
2 votes
1 answer
48 views

Efficient method to isolate open drain output from mcu

I'm using the LTC4418 power path controller My power sources include a solar panel which can produce voltages close to 30V. I want to send the VALID status outputs to my MCU but it is on a different ...
davegravy's user avatar
  • 439
0 votes
1 answer
45 views

I want to know R2 value wrt Vin and Vout of HCNR201 circuit

I'm trying to learn this circuit, it is HCNR201 (Source - HCNR201 High Bandwidth Evaluation Board User Guide). I want to calculate value of R2 w.r.t. Vin, Vout and HCNR supply. Specially trying to get ...
Bhushan Waghe's user avatar
0 votes
3 answers
58 views

Constant current opto input circuit [closed]

I have implemented the below circuit in a small project I'm working on which is based on a suggestion in another post, Optocoupler circuit accept input between 3-50 volt It all works fine with a ...
pspeirs's user avatar
  • 75
1 vote
1 answer
66 views

Monitoring an LED state from another circuit via an optocoupler in ESPHome

I am attempting to control a KVM switch using ESPHome on a D1 Mini ESP8266 board, so learning some electronics along the way. The KVM has the main unit and a controller on the end of a 4 core cable. ...
Ben Swinburne's user avatar
2 votes
3 answers
275 views

Controlling button press on key fob using microcontroller

I have a battery-powered fob remote, and I want to convert it from being operated via a manual button press to being controlled by a microcontroller. The fob looks like this: After making some ...
teeeeee's user avatar
  • 737
1 vote
2 answers
56 views

Opto-Coupler window detector with delay

I'm trying to build an isolated circuit that can detect high-voltage pulses within a certain duration window and active a low voltage side accordingly. The low-voltage side should activate for: ...
Malte's user avatar
  • 155
0 votes
1 answer
73 views

Watching an open-collector input without disturbing it

I'm trying to control an opto-isolator (actually a photorelay such as a TLP354x but it doesn't really matter here). The problem lie in an external device (black magic box) which is also controlled by ...
VoltsAndNuts's user avatar
0 votes
1 answer
45 views

Drive two bidirectional MOSFET constellations with the same optocoupler?

I want to create a solid state relay kind of circuit. The plan is to allow signals to pass through when active and not when inactive just like a standard relay. The issue is that I want to do this ...
ErikM's user avatar
  • 3
1 vote
0 answers
46 views

Shut down raspberry when unplugged from power thanks to a battery

Context and objective I need to properly shut down a Raspberry Pi Zero 2 W when it is (physically) unplugged from the power and power it on again automatically when it is plugged back. The basic idea ...
user3161330's user avatar
0 votes
0 answers
143 views

What analog component(s) can I replace a relay with

I'm extremely new to electronics and have a college group project to build a traffic light using only analog components (ICs are allowed), my subsection is to design and build the driver unit and a ...
OR13N 's user avatar
0 votes
0 answers
43 views

Optocoupled Input (3..24V) overcurrent/ESD Protection

I'm designing relatively wide voltage range (3..24V) isolated input for reading the push-pull output state. Input source is going to be from a water counter, some 3-phase motor controllers, water ...
Taras Shcherban's user avatar
2 votes
1 answer
181 views

Controlling a relay with a raspberry pi pin 3.3 V

Was look for a review to make sure I'm not doing something stupid. Looking at common relay modules on Amazon, it seems that something like this is going on. Would this work to control a relay from a 3....
Dave Fol's user avatar
  • 159
0 votes
1 answer
44 views

MOC3021M + JST16A-600B TRIAC Circuit problem: Resistor blowing up

let me clarify first than I'm no expert in electronics, so, I could be doing something really stupid here. I want to replace the control board of my kitchen extractor motor with a custom version that ...
KnF's user avatar
  • 25
1 vote
2 answers
105 views

Building SPICE models of optocouplers

Looking through this answer about the 6N137 optocoupler I wonder where one can get all those paramaters like Is, Rs, N, various internal resistances, etc. that are used to simulate the optocoupler. I ...
LevGor's user avatar
  • 13
0 votes
1 answer
90 views

I have a AD9833 function generator which has the ability to change frequency from 1k to 1MHz but a fixed 0.6V output I want 1V to 10V pk to pk

The frequency changes from the AD9833 DDS chip but it has a 0.6V pk to pk and I need it to be 1V to 10V pk to pk this is my circuit so far the goal is to have an adjustable gain please any adjustments ...
zug's user avatar
  • 31
1 vote
1 answer
88 views

Fan dimmer using MOC3021 and TRIAC suddenly stopped working. Cannot find possible reason. The circuit worked fine for two days

I am trying to control speed of a fan using MOC3021, BT136 and zero crossing detector. The circuit worked fine for 2 days and then suddenly stopped working. I am unable to find the problem in the ...
Aditi Kumari's user avatar
0 votes
2 answers
20 views

Does a pair of USB-tethered ESP32 (or cp210x) modules connected to each other need optoisolation?

Let's suppose I want to build a 21st-century null modem using a pair of ESP32 modules (or maybe just a pair of cp210x usb-to-serial modules) connected "back to back" (tx on one to rx on the ...
Bitbang3r's user avatar
  • 177
6 votes
3 answers
1k views

Faster alternative to solid state relay

I am currently designing a circuit that includes a solid state relay, the CPC1125 . I chose it because it is one of the faster normally closed solid state relays I found. I want it to be optical ...
DarkBulle's user avatar
  • 363
0 votes
3 answers
105 views

Capacitor can't filter the AC detector spikes

I made a simple design to read the status of an 220 V AC relay. I used a diode and resistor to drop the voltage for the PC817 optocoupler and used a capacitor to filter spikes: This is the test ...
Hamid s k's user avatar
  • 333
0 votes
1 answer
37 views

Optoisolator between uC y IR2110?

I am working on a brushless driver, which has 3 IR2110 as a mosfet driver and as a microcontroller I use a stm32f103c8t6 (blue pill board). Everything works correctly, but I have the following ...
Ariel Kinderknech's user avatar
2 votes
1 answer
149 views

AC amplification [closed]

document link: https://www.zorgeffects.com/index.php/en/blog/33-tremoloo-ooo-ooo-ooo-ooo How can I use this theory to amplify an AC signal? my project is run through a 5V supply hence the MCP601 rail ...
zug's user avatar
  • 31
0 votes
4 answers
147 views

Controlling relay through an optocoupler

I'm trying to control a relay through a TCMT4100 optocoupler but I can't get it to work. I tried to check the TCMT4100's datasheet, but I don't quite understand which forward current should I look for,...
k0cka's user avatar
  • 51
1 vote
0 answers
26 views

Arrangement of isolated variable DC input

I design isolated DC input for industrial applications that can possibly work from 12 to 24 V. I add a 5.1 V Zener for over-voltage protection, a capacitor for filtering, and TVS for surge production. ...
Hamid s k's user avatar
  • 333
0 votes
1 answer
25 views

Digital isolator: Output is not coming as expected

Im using digital isolator to isolate my PWM signals. Output VO does show any PWM output. What may be the issue here. I have used 1kohm at R1. Input side: PWM_H_In : PWM signal from function generator ...
Rohan Kharvi's user avatar
1 vote
1 answer
83 views

Detecting 220vac with optocoupler and microcontroller on lines that have capacitive coupling voltages

I'm a hobbyist, trying to instrument my heating system so that I can control a three position valve. I have an ESP8266 integrated with a DRV8825 stepper motor controller, and a no-name Chinese 220vac ...
Richard Appleby's user avatar
0 votes
1 answer
118 views

I want to drive half bridge using gate driver that doesn't use bootstrap method

First of all, it can be unnatural using a translator. I'm sorry. I'm trying to drive the high side switch through gate driver that doesn't use bootstrap method. I think we can use optocoupler type ...
kogyu's user avatar
  • 77
0 votes
2 answers
84 views

Snooping on an IR receiver with a microcontroller [closed]

I have got some PCB that has an IR receiver and processes that signal in a non-relevant way. I would like to intercept or snoop in on that same signal with an ESP8266, without affecting the original ...
Opisek's user avatar
  • 3
0 votes
0 answers
44 views

Tapping in between a brake lever and an e-bike controller

I'm designing a piece of hardware that resides between an e-bike controller and the brake lever. The difficulty is that the battery voltage is unknown and can be between 36-52v. simulate this circuit ...
Melvin van den Berg's user avatar
2 votes
7 answers
2k views

Why does my opto behave like this?

Can you help me explain why my opto (LTV-817S) is behaving like this? The schematic is shown below and the scope below that. We are using an STM32 communicating with an ESP32 via USART at approx 38400 ...
JoeyB's user avatar
  • 2,361
0 votes
2 answers
57 views

Do I need a pull up or pull down for the optoisolator in a USART application?

I have a LITE-ON LTV-816S optoisolator I want to use to isolate a USART communication channel. The inversion of case 2 is not a problem as I can handle this in software. Which case is better in terms ...
JoeyB's user avatar
  • 2,361
1 vote
0 answers
21 views

Selecting Optoisolator CTR for MPS MP8009 SSR Forward Topology

Do the optoisolator Current Transfer Ratio (CTR) Min and Max matter for this design, and if so, what is the benefit of selecting each ratio? Here is the MPS MP8009-GV PoE controller datasheet, inside ...
Wes Ellgass's user avatar
8 votes
4 answers
2k views

Can I stack optocouplers in series to make a higher specification part?

Yet again I'm working with the sub-set parts the PCB assembler house has pre-loaded, and not what is commercially available. Like using 3-6 resistors in place of 1, and more relevant to this question; ...
user1488660's user avatar
1 vote
1 answer
111 views

Reading 12-bit digital value through optocoupler

I am using an ESP32S3 to read the value of an S9706 color sensor. For some reason I had to add an optocoupler to my schematic after the sensor output. After uploading the code to my ESP32S3, the ...
Hamo's user avatar
  • 41
1 vote
2 answers
77 views

24 VAC signal rectifier and detection

One of my projects consists of recovering a 24 VAC signal to give a run command. To avoid using a relay with a 24 VAC coil I would prefer to convert the 24 VAC signal into a DC signal and use an ...
Benito's user avatar
  • 41
0 votes
1 answer
79 views

Can a MOC3032M optocoupler be used to generate a DC PWM signal?

I'm trying to make a circuit that can output an 80 Hz PWM signal. I'm planning to use an Arduino to switch an optocoupler that will control the duty cycle. Here is my circuit: After building the ...
jjk's user avatar
  • 123
2 votes
2 answers
429 views

Which is the best method to measure AC voltage?

I am trying to make a UPS circuit. I need to have a high speed measurement for the input AC voltage (220 Vrms) (in order to know whether to turn on/off the inverter). I had tried using this circuit: ...
Hazardous Voltage's user avatar
1 vote
0 answers
75 views

MOC3021 stopped working

I am trying to make a dimmer circuit using an MOC3021 and a BT136. I used a zero crossing detector with a 4N35. The dimming is controlled with a processor. Initially the circuit worked fine, but ...
Aditi Kumari's user avatar
0 votes
0 answers
46 views

Optocouplers for comparator as current detector

I'm working on the realization of overcurrent detection that will be powered by a battery supply. I successfully simulated a comparator with an operational amplifier that will set the output high when ...
Simplifier's user avatar
0 votes
1 answer
211 views

What happens if two linear optocouplers are paralleled, if their output voltages are different?

If the outputs are connected, what voltage would be detected at the combined output? The higher voltage? Or, would the lower voltage device malfunction in some way? Hoping to see the highest voltage ...
johny why's user avatar
  • 176
2 votes
1 answer
102 views

VOM617AT SPICE model not working

I downloaded the VOM617AT (optocoupler) SPICE model from the following address: https://www.mouser.com/ProductDetail/Vishay-Semiconductors/VOM617AT?qs=9vrc9xEJKyxW%252B%2FlvaQ%252BSPg%3D%3D I am not ...
nmr's user avatar
  • 123
0 votes
0 answers
100 views

Driving Gate from MCU (using 6N136 and TC4431)

This is my first time trying to use this optocoupler (6N136) I'm trying to control a MOSFET gate with the least switching delays (rise and fall timings) possible, while making the MCU isolated from ...
Bikay's user avatar
  • 73
1 vote
1 answer
63 views

H11L1M optocoupler is inverting

I'd like to protect a serial connection with a H11L1M (I can easily get some at work and it works from 3 to 16 V). The problem is this optocoupler is inverting and has the following truth table: ...
Manitoba's user avatar
  • 223
0 votes
2 answers
67 views

Design Suggestions for an Optocoupler Relay Module

I have designed this module to operate with input voltages of 5V and 3.3V (common in most MCUs). Additionally, I have equipped it with an optocoupler to isolate the MCU from the power section of the ...
Luis J. Mora's user avatar
4 votes
2 answers
727 views

What's the circuitry inside triac driver optocouplers?

When looking through datasheets I can't find a single one that shows the inner circuit of a triac driver optocoupler, all I get is this common diagram: What that zero crossing circuit looks like? how ...
ElectronSurf's user avatar
  • 2,376
4 votes
3 answers
662 views

Optocoupler as a switch for composite video sources

I want to switch between 2 video sources (cameras) to a common video receiver. Is general purpose optocoupler suitable for that? Here is the schematics: In more details, the video switch is ...
brigadir's user avatar
  • 271

1
2 3 4 5
24