Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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.

-1
votes
0answers
40 views

Isolated voltage sensing

I'm in the process of building a battery powered, uC controlled power supply. I'm using a bluepill basically and an xl4016 buck converter module. To my assumption I can just tap in his regulation pot ...
0
votes
2answers
99 views

How isolation is achieved in isolated channel oscilloscopes?

I tried to search something about this but found only a small amount of information. What confuses me is that all isolation amplifiers, optocouplers etc. I could find usually work at much lower ...
0
votes
1answer
43 views

GPIO connected as open-drain to opto-isolator's cathode

When connecting GPIO output pins (RPi, uC, ...) to an opto-isolator, the classical way I know is the following (at least I understand that it can roughly be depicted like that): simulate this circuit ...
0
votes
1answer
64 views

Voltage sampling from 220vac to 5vdc

I made a 1 phase to 3 phase inverter using arduino and IR2104 to control the speed of an induction motor and it is working perfectly. To complete the protection scheme, I need to monitor voltage of ...
2
votes
2answers
65 views

Help understanding power ratings in optocoupler datasheet

I want to understand this the datasheet for the Everlight EL817 optocoupler but don't know what is the maximum power can the output hold. I see an optocoupler as a kind of switch that closes a ...
1
vote
1answer
49 views

How much current does this Opto isolator output (HCPL-3180)?

I wanted to use it like this in this configuration][How much current does this Opto isolator output (HCPL-3180) ?
2
votes
3answers
54 views

optocoupler - Does the current limiting resistor of the led make a difference

Does the led current limiting resistor for the led make a difference to the performance/behaviour of the optocoupler? Is it just like how a normal transistor would work, if you drive the base harder,...
0
votes
0answers
35 views

Opto-coupler and switching digital pins

I'm a total noob when it comes to the use of opto-couplers, but I'm trying to connect up a couple of digital pins between an ESP32 and a small voice module. There are two pins that I need to switch ...
0
votes
2answers
41 views

Interpreting some functions of an optoisolator from its datasheet

I cannot interpret couple of things from the datasheet of this optoisolator. 1-) Is there and hint in the datasheet regarding the maximum CM voltage interference it can handle at its inputs? 2-) The ...
0
votes
0answers
41 views

LED and optocoupler MOSFET switch connected with an inductive load

I want to ask, if this circuit will work. I think the flyback from the inductive load the mosfet is connected to will break the optocoupler. The LED is connected through a resistor which should ...
0
votes
1answer
30 views

Opto-coupler to convert current into voltage

I am using TPS26601 for my next design. There is a pin IMON which outputs current proportional to current flowing throwing the output pin. The gain ranges from 72 ...
-1
votes
0answers
42 views

Need help checking the schematic of buck converter

I designed this circuit to work as a buck converter, using atmega32a as a controller to get PWM with 500k HZ and 47% duty cycle, my problem is that I am not sure how to connect between the control ...
2
votes
0answers
47 views

Sizing the input current of a isolated standalone MOSFET gate driver for a stable output

After a suggestion from my previous question I'm planning to use this Photovoltaic isolated MOSFET gate driver to trigger a trigger input of this DAQ. It seems these devices do not require an ...
0
votes
1answer
36 views

Can there be workaround for opto power supply which is not local with the receiver input?

I'm stuck with an issue.. A 0-5V 33Hz pulse train need to be interfaced with an optocoupler 4N46 before it reaches to a DAQ input. This is need to block common mode EMI which introduces noise at this ...
-1
votes
0answers
18 views

PWM Opto-Isolator Inline Volume Control for external source to Amp (Rpi Project)

My project uses a Raspberry Pi to mute a stereo audio source (could be a CD Player, iPod etc. at line level) that is connected to an Amp. This takes place at specific times of the day. Wait a ...
1
vote
1answer
41 views

Optoisolator Not Switching

I’m working on a university project that involves switching a relay using an ILD213T optoisolator. The optoisolator is driven directly by an ATmega328p. I had calculated the required current limiting ...
0
votes
1answer
51 views

Using Opto-Coupler with STM32

My question might be already answered but I have some problem with resolving it. I'm using PC817 Opto-Coupler to turn on a relay. My VCC voltage is about 4.2 volts and the MCU is an STM32F4 with 3.3v ...
0
votes
1answer
43 views

MOC3021 optocoupler not working ( or not working , a bit confused )

My Understanding As far as my understanding of MOC3021 optocoupler goes, it should latch pins 4 and 6 whenever there's a current flow between pins 1 and 3. The Confusion Image 1 - D1 not glowing ...
-1
votes
0answers
33 views

Parallel Triac driving same Inductive Load NOT Working?

As per the schematic two same value triacs and driver circuits are connected parallel, Triacs are BTA24 and Opto-couplers are moc3021 and the load is inductive, when i trigger the MOC U1 the Triac Q1 ...
0
votes
0answers
60 views

Ground Test with MID400 (Optoisolator)

I design my controller, one of the tasks of which is to check the operability of grounding in an AC line. The controller will be built on the basis of ATMEGA328P (Arduino UNO), in the high-voltage ...
0
votes
1answer
45 views

Opto-Isolater always on by higher voltage

I use an AQH3213 Opto-Isolater. When I use 3.3V on the 'dc motor side', everything works fine and it 'turns off and on in an interval of 1 second'. But when I use 5V, it's always on.... Do you have ...
1
vote
1answer
55 views

Noninverting optocoupler with a pulldown resistor

I am using a power MOSFET to switch a solenoid valve. The MOSFET is driven with a optocoupler (LTV-847) to isolate the 12V required to switch the valve from the 3.3V used by the microcontroller. ...
0
votes
1answer
102 views

microcontroller is “hanging” when it is feeding PWM to a DC motor controller

I am using linear potentiometer to control the speed of a DC motor. I am using the following schematic. An ATmega328P receives the value from linear potentiometer via analog read. This ATmega328P ...
2
votes
2answers
93 views

How series resistors influence clearance-creepage requirements?

simulate this circuit – Schematic created using CircuitLab I'm designing a circuit which should leak some amount of current from AC line to PE. The question is regarding clearance-creepage ...
6
votes
3answers
1k views

No current through AC optocoupler

I am just testing this component MOC3021 optoisolator, its datasheet can be found here. This is my circuit in Proteus: Please forgive me for my ignorance of electronics, I have my background in ...
1
vote
0answers
28 views

phoresistor vactrol tremolo noise

I made an optocoupler by shrink tubing a generic photo resistor and a cold white led. Then used it in the following setup to be able to control audio level to achieve tremolo effect: simulate this ...
0
votes
1answer
27 views

Circuit to a/b switch like a relay would. So an analog or digital signal can be turned on or off or routed

I need to build an arduino-based switcher / router for a multi-arcade to route controls to different game boards, and also switch 2 vga inputs into one output. Without introducing any lag also. 3 ...
4
votes
2answers
120 views

Using optocouplers at the end of a twisted pair

I am designing a dumb "isolation box" that is to sit between a computer and medical data acquisition equipment. The purpose of this box is to inject power and to provide communications and digital ...
0
votes
2answers
57 views

What is optocoupler and how it is used? [closed]

Im curious about optocoupler. What is optocoupler,why and how it is used in electronic circuits ?
0
votes
1answer
45 views

What does “off-state output terminal voltage” in optocouplers mean?

I was looking at possible options of what optocouplers to use in my project. I was looking at these parts. https://www.fairchildsemi.com/search/?searchText=MOC3023-M#N=&&Nao=0&&Ntk=...
0
votes
1answer
46 views

Achieve -12~12V PWM Signal isolate

I have used IL300 to isolate 0~5V PWM signal before and it works great. The circuit is shown below. But now I need to isolate -12 ~ +12V PWM signal. Is there any possibility or suggested circuit to ...
0
votes
1answer
60 views

Transistor Reverse Biasing - AC

I am working on a project which require to activate a 24V Rated relay using a 3.3V rated IO. To provide adequate isolation I have added a Opto-isolater stage. In order to increase the current output ...
1
vote
1answer
83 views

Detect phone call termination

I am designing an automated telephone circuit that will work with the PSTN line. I already had a question to detect the incoming ring signal. Now I want to detect whether the opponent person in the ...
1
vote
1answer
50 views

Operating a 24VAC solenoid with a Triac. Protecting with TVS DIODE, RC Snubber or both?

As part of a project I am controlling 24VAC solenoid sprinkler valves like this https://rayshobby.net/wordpress/understanding-24vac-sprinkler-valves/ using a triac (BT1308W) http://www.mouser.com/ds/2/...
0
votes
3answers
80 views

Problems sizing series input resistor for this optocoupler

Under the electrical characteristics, the optocoupler 4N26 typical "forward voltage" is given as 1.2V. But for sizing the input resistor Im have hesitations. In my application as a control signal I ...
3
votes
2answers
134 views

how do I use H11L1 correctly to receive MIDI?

I was following this schematics. This is the first result on google images My Arduino Serial Monitor received nothing. I tried to replace the H11L1 with LED, and it does blink. but as soon as I ...
0
votes
2answers
62 views

A question about using optocoupler instead of FET for longer signal wires

After my previous question I had concluded to use the following circuitry to operate this solid state relay: But now I found out that, from the micro-controller(Arduino UNO) digital output pin to the ...
0
votes
1answer
87 views

Overvoltage protection for AC relay dilemma

I am currently designing a safety-related device that has to open a relay when a certain event occurs. During most of its life, this relay will be closed, and only open if the safety event occurs, ...
0
votes
2answers
37 views

Isolate a digital signal that changes its amplitude

I have to isolate a digital signal that has the following characteristics: frequency: between 1 and 1000 Hz amplitude pk-pk: 12V offset: 0-6V With "offset" I mean the actual voltage may change from ...
0
votes
2answers
103 views

Component values

Can somebody clarify the following points for the MOC3041 sample circuit given at their datasheet: What are the wattages of resistors at the HOT side What is the difference between 360Ω and just 330 ...
1
vote
2answers
125 views

Is this optocoupler front-end safe?

This is a follow-up to Is this line detector safe? I'm re-designing the front-end based on some great feedback from the community. I've decided to move to the following topology: The phase of the ...
1
vote
4answers
147 views

Is this line detector safe?

I'm thinking about building a basic AC mains voltage detector. I'd like for it to be both protected and isolated, so I have a zener TVS and an optoisolator. R1 and R3 are chosen so that between them,...
2
votes
1answer
131 views

Measuring individual cell voltages in a series cells Battery

I'm making a 600V battery, and I'm trying to design a Battery Monitoring system, that measures (and keeps log of) each cell's voltage turn by turn, in a series configuration of 162 lithium cells. 162 ...
0
votes
1answer
113 views

Creepage Distance in Altium Designer

I have a design with a high voltage and a low voltage part. Between the two I need to have a creepage distance of 8mm. Some optoisolators I use in my design are not wide enough on the PCB footprint, ...
0
votes
1answer
31 views

Driving multiple loads with a single TRIAC and multiple optoisolators

I simulated this circuit in multisim. It is working fine. However, I am just curious to know if it is possible to drive multiple loads with multiple opto-isolators with single TRIAC? Something like ...
1
vote
1answer
81 views

TRIAC won't turn on/turn off

I'm trying to make simple lamp switching circuit to work, but it just doesn't want to work as intended - question is, why? I'm using MOC3021 random phase optotriac with BT136/600E sensitive gate ...
0
votes
1answer
49 views

Trigger input with varying input voltages

Currently I am trying to build a circuit, with the goal of triggering a pin of an ESP8266 from varying input voltages (in the range of 5 to max 15 volts it should get triggered). Also the input should ...
0
votes
0answers
76 views

How much current does an LED in optocoupler draw?

I am planning to actuate the relay (opto-isolated) using the GPIO pins of Nodemcu. NodeMcu's datasheet says that maximum current that can be drawn out of a GPIO pin is 12 mA. Any load more that may ...
0
votes
1answer
89 views

Sense 230V - voltage

Brief sum up (you can go directly to the end if you already read the sum up in the other question) For a home project I'm making a controller to drive a two-direction 230V motor. For those unfamiliar ...
8
votes
4answers
2k views

Detect 220 VAC with a Raspberry Pi

I want to build a simple device to check if the light is on or off. I found some schematics but I need to be sure that it is safe. Source : How to detect 220 VAC voltage using an opto-isolator My ...