2669Views13Replies

# Optocouplers for mains?

I would like to know if i can use an optocoupler instead of a regular relay?

Like on one side would be an arduino and on the other would be 220 v ac to control a light for example

Is this setup possible?

2669Views13Replies

I would like to know if i can use an optocoupler instead of a regular relay?

Like on one side would be an arduino and on the other would be 220 v ac to control a light for example

Is this setup possible?

## Discussions

Best Answer 4 years ago

Yes !

Here is a circuit that uses any uP output pin.

to turn on an incandescent light bulb.

A

Answer 4 years ago

BTW the 470 ohm resistor does not need a lot of power.

That is because as soon as

gatecurrent flowsthe

Triacswitches into conductionandthere is no more voltage across the power pins::-)

Answer 4 years ago

Brilliant , so can i use the MOC3023 and the bt137 with the 470 ohm to switch mains ? 200v upto 10 amps?

Answer 4 years ago

sorry 220v 10 amps and also what about fans , like a ceiling fan , can i use the same setup to control that as well?

Answer 4 years ago

The MAC12 with 12 amps RMS is better then the BT137 at 8 amps RMS. It will take 65 amps start up serge but the BT137 will get hot at a constant 10 Amps.

Answer 4 years ago

Thanks , i did a little research and i found out something about a snubber circuit , do i need that for a ceiling fan ? what about a table fan?

Answer 4 years ago

If there isn't one in the fan already yes. Some adjustable speed fans have snubber circuits in them.

Answer 4 years ago

Answer 4 years ago

Oh my last question , Say i use the MOC3023 and the BT137 , what can be the maximum limit i can push this system to before it causes any problems?

Answer 4 years ago

Well your mains are 220 AC volts so the BT137-500E should be fine it is 8 amps RMS (running current) and 65 amps surge or start up current.

As long as you do not run it for a long time over 8 amps it should be fine.

The MOC3023 is also fine for running the BT137-500E

You can get the datasheets here:

http://www.maxim4u.com/

Answer 4 years ago

Yes you can control a ceiling fan !

and with no annoying relay clicks

or sparks that could cause a fire.

4 years ago

A Triac optocoupler like a MOC3010 to a Triac like BT137 will do 8 amp RMS or a MAC12 for 12 amps RMS.

The finish Triac current and gate current are your challenge.

4 years ago

I would like to thank both of you for taking your time to clear my doubts and explain what i didnt understand

Thank you

Aki