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.

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102 views

Optoisolator, did I connected it right? (Arduino Uno)

Here is my connection for optoisolator, 2 wires, yellow and red are for AC current. Other 3 in my arduino, orange pin 2, blue ground and red 5V power. And ...
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2answers
108 views

How to test if zero crossing is working?

I used circuit like this: On led I get: 3.3 mA and 1.3V What is the best way to test if zero crossing works with arduino or multimetar?
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1answer
82 views

Using optocoupler with MOSFET for dimming a LED

I have a blue LED which I want to dim using an Arduino, an optocoupler and an N-MOSFET. For achieving this I assembled the circuit on a breadboard as shown in the pictures, using a YwRobot breadboard ...
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1answer
40 views

Arduino input with CNY17 to sense 12v input

I have an Arduino Due and i am using a CNY17 optocoupler to sense a 12v brake signal from a car. The 12v signal is going thru a 1K resistor to the opto on pin 1, pin 2 to the ground. 3.3v is going ...
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2answers
45 views

Optocoupler w/ RasPi & Door Buzzer

I'm currently trying to make a system where sending a message to my Raspberry Pi from my phone will send a signal to my apartment's buzzer to open the front door, however I've been having problems ...
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39 views

why is there a dc shift in the output of the opto-isolater?

I have pc817 ...input is 0 to 5 v and the output is 0 to 5v with dc shift. pin 1 and 2 is connected to an arduino with a resister on pin 1 150ohm pin 3 ground and pin 4 resister 150ohm + Vcc 5v.. so ...
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2answers
54 views

Optoisolator Long term Reliability at HVDC

Most optocouplers spend most of thier time isolating mains voltages.They are reliable doing this and they are cheap and simple.How would things go if the same garden variety opto was isolating a DC ...
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1answer
50 views

4N32 Opto-Isolator Questions

I am looking into using a 4N32 opto-isolator and am struggling to find information on its pin 6. This looks to be the base of the transistor (darlington). I see example circuits where they appear to ...
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1answer
80 views

How Zero Crossing optoisolator to work with 220VAC?

I want to use a H11AA1 to detect Zero Crossing, but I am not sure how circuit should look like. How much voltage should LED receive inside H11AA1? Here is datasheet: ...
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37 views

what is the best way to protect sinking inputs

I have a controller with sinking inputs ( should be grounded to activate) , I will use the system in a noisy environment, I want to protect these inputs from EMI and voltage spikes, what is the best ...
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3answers
112 views

Optocouplers with non-inverting logic

Here is the setup: I'm using the Arduino Mega's SPI functionality to send signals to multiple DACs. For digital isolation, I am considering the HCPL-2631 or the ACPL-064L. The problem with these two ...
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1answer
47 views

Power rating for opto-triac trigger circuit resistors

RHS will be using 220v 400watt bulb 2 simple questions 1- does the 360ohm resistors has to be of high watt too ? 2- all i can find is 5-10watt resistors, can i use them ? would they snub correctly ...
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42 views

Opto Coupler output voltage drop when connected to PLC

I have an input of pulse width 5 ms and which is fed to a Buffer IC and then the output of the buffer is FED to an opto isolator whose collector is pulled with a pull up of 7.5k resistor with an 24 V ...
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0answers
49 views

220V AC Light Dimming(triac H11AA1, MOC3052-M)?

Could I use triac H11AA1 and MOC3052-M to control 220VAC with arduino? I am new to electronics and I am not sure if that components can handle the voltage... Also could you show me some circuit with ...
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3answers
59 views

Using an opto-isolator in a car's circuit. How to ground?

So I have a microcontroller that will read some of the car's sensor output (0-5v) and i plan to send the signals through an opto-isolator. The problem is that when i simulate this, it seems i cannot ...
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0answers
59 views

How to control AC high voltage with Arduino?

I found this great post: http://majsterkowo.pl/en/how-to-control-any-home-appliance-using-a-tv-remote-and-an-arduino/ and this scheme: ...
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2answers
59 views

Optocoupler Question

I'm currently trying to create a system to open my apartment's door (using the buzzer) using my raspberry pi, and thought that using an optocoupler would be the best solution - although I'm a complete ...
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1answer
94 views

uC-controlled high-side switch

I designed a circuit that powers on when the car is started (key is in ACC or ON). The circuit's uC then enables 12V from the battery by setting port PC5 high. The uC detects when the key is ...
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1answer
39 views

Totem pole opto-isolator TLP152 won't work as intended

I've been working on this very confusing problem regarding making a TLP152 opto-isolator to work as intended. Here is my circuit using a TLP152 to work as a IGBT gate driver. TLP152 circuit diagram ...
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2answers
44 views

Exceeding _Enable input voltage_ of optocoupler

I have microcontoller board with following optocoupler interface which is obviously made for input up to 5V. Based on datasheet I found, Vf = 1.5 V and ...
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3answers
89 views

Recommended capacitor rating for this mains zero-crossing detector

I found this zero-crossing detecting circuit here I want to recreate it, using the parts that I have on hand (or can get cheapest), but I'm not sure how to choose the correct 0.1uF capacitors. ...
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2answers
81 views

Timing Issues with Optically Isolated Data Signal

I have been working on a system that requires data transmission between two devices powered by separate supplies. I have based my design on the MIDI-hardware Spec, as I'm comfortable working with that ...
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4answers
96 views

Opto-coupler output

I am using this circuit for mains detection: The output fluctuates a little but capacitor and resistor values ensure that Output is logic HIGH when 220V mains is present. Once mains is not ...
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2answers
110 views

optocoupler output protection

I've got this circuit. The target generates an identical PWM signal to control the intensity of 3 LEDS. But I would like to protect the output of these optocouplers with this TVS: I'm not sure if ...
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1answer
59 views

Hey I am using 2 4N35 Optocoupler from Visha can I replace them with a single ILD615 from Vishay?

I went through both datasheets and i think it should work. Basically I am asking if the dual channel version of 4N35 is the 8 dip ILD615. Thanks. edit: I have added the picture. my circuit is like ...
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1answer
39 views

normally open or normally closed OptoMos

In the following OptoMos datasheet the OptoMos is defined as Normally closed, when there is no input the output is closed. But in other OptoMos like the SFH618A-2 i can't find if the OptoMos is NO or ...
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1answer
57 views

How to use same 'input' for two circuits

First of all, please excuse my complete lack of knowledge in electronics :) Let's start with a little bit of context. I am trying to modify a machine that already uses a photo-interrupter to measure ...
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0answers
39 views

Adding resistor in parallel to digipot

I'm trying to control a device using a digital potentiometer (AD5245S). In my application I can't tie the low-ref of the potentiometer and ground, so I'm using an I2C optical isolator (ISO1541) to ...
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1answer
79 views

Converting 5 volts to 12 volts using a photocoupler

i have an arduino and i need to convert 5 volts to 12 volts in order to trigger a 12 volt Rele, i am considering to use the circuit that i attached here (below), if the "input" square is 5 volts, what ...
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2answers
36 views

Do I need TVS with Optocoupler relay

I am connecting digital output from a camera to a light source using a relay (see below). The relay uses SONGLE SRD-5VDC-SL-C Optocoupler: RELAY DATASHEET The camera manual says "Uses an ...
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1answer
99 views

Voltage Regulation

I am a young engineer and I need a help from you. I need to design a driver circuit which must power-up a LED (OC) if the measured volatge is greater that 50V (Voltage to be measured can be upto ...
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1answer
69 views

OptoIsolator Reliability?

I have heard it from multiple people over the last 5 years that Optoisolators are failure prone and should be avoided when able. I'm working on a project (for personal use) that I was going to put an ...
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2answers
70 views

Severe Voltage Drop When Applying a Load to Opto-Isolator Circuit

The circuit below uses the Vishay ILD213T optocoupler (datasheet). The load in question is a 5V solenoid valve with a resistance of 46Ω. The circuit is configured with "IN1" connected to a GPIO pin ...
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132 views

Opto-isolator output from collector vs. emitter

I have an Isocom ISQ2X quad opto-isolator (datasheet) that I will use to drive a logic input. The opto-isolator's simplified model given by the datasheet is pictured below. The transistor base pin is ...
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2answers
97 views

Use a PC123 optocoupler for MIDI input

Im trying to connect a MIDI input cable to an arduino. To do that, I need an optocoupler, that secures the internal circuits from damage. This is the schematic as shown by the MIDI specification: ...
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2answers
81 views

Design of AC measurement circuit

I posted a question earlier, How to measure AC voltage without a voltage divider using microcontroller and I got some very useful answers, one of those was to implement this for isolation ...
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1answer
28 views

Optical switch operation point derivation

I have an optical switch part opb840W and I am failing to derive the required information for my application from there. The intended use would be as in the following circuit: simulate this ...
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2answers
410 views

What is the correct way to measure voltage with an optocoupler?

I'm using an optocoupler to measure a voltage, I'm making a current loop to control the current through the LED, so I'm using three op-amps: one to measure the voltage, one to set up a current offset ...
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2answers
218 views

Driving a 24V isolated load from a 3.3V MCU

I am looking to drive a 12-24V purely resistive load from a 3.3V MCU. I would like to use an opto-isolator to separate the circuits electrically. I've drawn up the following circuit, but I'm not ...
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1answer
52 views

Accidentally outputting to an optoisolator

It's your friendly electronic hobbyist again. I am designing a board where I am reading input from an optoisolator like this. IN7 is connected to a peripheral parallel port chip of an old 8-bit ...
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3answers
82 views

Isolated mosfet switching circuit

I have designed the circuit below for a isolated digital output from a mcu. The switching speed is slow -- only 100ms or so. I would like to be able to switch between 3 and 24Vdc at about 1mA to ...
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2answers
98 views

Combining Optoisolator and Relay into one I/O pin

I have a project that uses two microcontroller pins to control the input and output of an isolated device. The LEDs are for status, showing when an input or output is enabled. I'd like to save some ...
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1answer
53 views

How to adjust output resistance with galvanic isolation?

I need to control the device (lighting LED driver) with 0-10V input. It looks like the driver has 100 uA current source as it can be controled with 0...100% PWM, 0-10V or 0-100kOhm resistance: So ...
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0answers
73 views

How to isolate Data / GND between WS2811 LED IC and MCU

How do you isolate the Data and GND lines between an MCU and a WS2811 LED Driver IC? The W2811 is another system that I will be interfacing and need to maximise protection to this. Bandwidth is not ...
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2answers
54 views

Switching two optocouplers based on different voltages

I want to build a (I think) simple circuit where I want to transmit the state of two switches across two wires (ground and live). Let's say I have a circuit with which I can set three output voltages ...
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1answer
87 views

Multiple ground planes with optocoupler

I'm designing a circuit that uses an optocoupler to isolate a relatively noisy H bridge from the USB circuitry also present on the board. Clearly in this case I will have two grounds - what is the ...
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1answer
59 views

In the given circuit of a regulated power supply, why is error computed twice, i.e., before and after isolation?

Circuit Operation \$R_4\$ and \$R_5\$ constitute the potential divider which is fed to the error amplifier \$A_1\$. The reference voltage is generated by the Zener diode \$Z_1\$. The error signal is ...
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1answer
126 views

What are the differences between optoisolator output styles?

Digikey lists optoisolators with several output types: Darlington Darlington with base Photo FET Photovoltaic Photovoltaic, linearized Transistor Transistor, with base What are the differences ...
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101 views

Opto-characteristic for schematic

I am referring below circuit, where I am using P781 opto-isolator. H1G is I/O pin from LPC2138 controller.( VCC for LPC is 3.3V ) J24: 12V,6W Heater Link for opto datasheet: ...
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39 views

Calculating the resistances of an optoisolator

How to calculate the resistance values of an optocoupler?? The optocoupler used is SFH6156-3. The output collector is being connectd to a 5V supply.A pulldown resistor is also connected to the ...