how to controle 220vac with 5vdc without using any kind of relays?

Thread Starter

vinay sv

Joined Nov 16, 2020
Someone may please assist with our problem, as I was creating a switching circuit for ac voltage supply where the electronics spacing is very minimal and I need to control my 220v of 300W ac supply with a microcontroller but we couldn't use any relay for it.


Joined Aug 1, 2013
No matter what you call it, there will be some kind of device that is controlled with a low power signal and switches a high power signal. Relay, solid state relay, high-power opto-coupler - whatever. A circuit that uses power MOSFETs will run cooler than any TRIAC circuit, but cost more.

At 220 Vac, 300 W is less than 1.5 A. Nothing you can build from scratch will be smaller or cost less than a 2 A relay.



Joined Aug 7, 2020
If space is the constraint, don't forget legal requirements of creepage and clearance distances on your pcb.


Joined Feb 3, 2012
Does your 300W AC supply have an isolated "enable/disable" DC signal input?
If so buffer your microcontroller output and drive the enable input low.