I want to use Arduino digitalwrite to turn on/off 24v ac circuit using an optocoupler. In this case I want to use Arduino's digital pins (DC) to switch a circuit on and off by way of anode cathode pins and on the collector emitter side, turning on/off, say a 24v AC circuit. Since on the AC side, cur…

@Paul_KD7HB While some SSR's provide circuit isolation, none of them cost 25-45 CENTS each like most optocouplers.

Hi, Welcome to the forum. What is the load you are switching? Please read the first post in any forum entitled how to use this forum. http://forum.arduino.cc/index.php/topic,148850.0.html Do you have any code written? Do you have a circuit made? Thanks.. Tom... :slight_smile:

Sorry, I thought I provided enough information for the question at hand in my first post. I have not written any code or have a circuit made yet because I don't know what optocoupler to use. I want to use an Arduino Uni R3 digital IO pin to turn on AND off the relay on a 24V AC irrigation valve that…

An irrigation valve is likely to use an Amp or more. We need a specification for the actual current it's going to use. I don't know of any cheap optocouplers that can switch that kind of current. They're usually used to switch a relay or Triac which then switches the main current. A combined device…

4-pin or 6-pin DIP-style dual mosfet based SSRs are usually <120mA. The 230volt SSRs you see on relay modules have a minimum voltage (~75volt). Post a link to the valve. Leo..

Here is the tech datasheet for the 075-DV Rainbird irrigation valve. ts_dv-dvf-asvf.pdf 337.36 KB It states on Page 1: Electrical Specifications • 24 VAC 50/60 Hz (cycles/sec.) solenoid • Inrush current: 0.30 A (7.2 VA) at 60 Hz • Holding current: 0.19 A…

The PC817C is a DC/DC only chip Do not apply AC you will kill the chip You do not need to use an opto coupler in this application. If you think there may be a problem with Richard Head ( a typical user) connecting the wrong thing use a polyfuse There are a number f cheap SSR's that will deal with …

You can use an opto - isolated triac such as a MOC3021. There is only a problem with the output not turning off if you have the output connected to a DC circuit. Because you are using AC, then the output will turn off when the current falls below a certain threshold. This will occur 100 or 120 tim…

@JohnLincoln , One of the optocouplers I was considering was the one you recommend trying, the MOC3021, but I discounted it because of the problem of it not shutting off I read on the interwebs. I did not realize those problems were for people trying to use it in a DC circuit! I will look into this f…

Help selecting optocoupler DC input to AC output

Projects General Guidance

Paul_KD7HB August 30, 2017, 7:45pm 2

Why are you so FUSSED UP about not using a solid state relay?

Paul

Topic		Replies	Views
24vac solenoid valve activation with 3.3v arduino General Guidance	25	4848	May 5, 2021
Review of my "Optocoupler as Relay Board" circuit General Electronics	55	5673	February 4, 2022
DC power switching General Electronics	32	433	April 18, 2025
Ideas on running an opto-isolator across a wide voltage General Electronics	57	2116	June 9, 2024
I don’t know what I am doing wrong ! General Electronics	27	516	March 3, 2025

Help selecting optocoupler DC input to AC output

Related topics