After a research on MOSFET use, I've found that I'm unable to connect load on Source in N-type without additional consideration.

About this component CPC1002N http://www.ixysic.com/home/pdfs.nsf/www/CPC1002N.pdf/$file/CPC1002N.pdf

I've a MOSFET driven by a LED, N-Type. This component is described as Relay, in this case should I take in consideration that load still need be on Drain becouse there's MOSFET inside? Or can I put load where I prefer since Vgs is given by an optocoupler?


1 Answer 1


A mosfet (so, also in the solid state relay) has a substrate diode that conducts when the source potential is higher than the drain potential. So, care should be taken how to connect the "load".

When you have a SSR made off two mosfets arranged back-to-back with their source pins tied together, their substrate diode are anti-series and it will not matter how the "load" is applied.

enter image description here

  • \$\begingroup\$ So, as I understood, doesn't matter if in CPC1002N I have a diode as gate or there's relay written on datasheets. It acts like a normal MOSFET with optoisolated activation. \$\endgroup\$
    – Singed
    Apr 11, 2019 at 12:55

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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