1
\$\begingroup\$

I am designing light control board using micro controller.As I want to make my circuit board smaller, So I am thinking to use Optoisolator or Optocoupler instead of using Relays. So please let me know, is it fair to replace "Relay" with "Optoisolator" or "Optocoupler"? Can Optoisolator work on more Amps?

\$\endgroup\$
  • \$\begingroup\$ I think you meant solid state relay or TRIAC. \$\endgroup\$ – Ryan Griggs Dec 27 '16 at 10:58
  • \$\begingroup\$ Relay can be both SSR and general Relay and replacement with Optoisolator and Triac...@RyanGriggs \$\endgroup\$ – karanrp Dec 27 '16 at 11:07
1
\$\begingroup\$

If your load is AC AND low power then some opto-isolators will work such as the MOC3021. It has a triac output capable of driving a low power load in the order of a few mA but, more likely you would want to drive a more powerful device such as this: -

enter image description here

The external triac would typically be a BT136 and there are a pile of google images here that show this type of configuration. The BT136 comes in a T0-220 package that isn't that small but maybe some space saving can be achieved. A lower power BT131-600 could handle 100 watt loads but RMS current is limited to below 1 amp. It is available in a T0-92 package.

You could also consider using a solid-state-relay although a lot of them will contain pretty much the above Triac circuit or back-to-back MOSFETs: -

http://www.bristolwatch.com/ele2/acdcssr/4a.png

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.