Hello i'm fairly new to electronics and I'm currently trying to use a S26MD02 Relay from Sharp as a Switch with DC sources. The main problem is that I dont understand the schematic diagram provided as it does not show mosfets inside as I'm typically used to seeing. enter image description here I have tried a few different topologies but cant seem to get it to work. This is a basic diagram of what I'm trying to achieve. I simply want it to turn on an LED on and off for a very specific purpose I need to use a relay. However i'm beginning to think that this relay is only for AC sources? And wont work with DC?


simulate this circuit – Schematic created using CircuitLab


1 Answer 1


Indeed this SSR (solid state relay) will not work for your application. This device is designed to switch AC, not DC. The switching devices are TRIACs, these consist of two antiparalel Thyristors.

Thyristors and TRIACs are switching devices that only can be turned off when the current turns zero. This happens 100 or 120 times per second when using the mains AC. But not in your DC application. Probably the trigger voltage (at which the TRIACs switch on) is also significantly higher than the 5 V you're using.

So you will need to use a different device.

  • \$\begingroup\$ That you for your help! \$\endgroup\$
    – user100041
    Feb 11, 2016 at 12:17
  • \$\begingroup\$ My pleasure :-) \$\endgroup\$ Feb 11, 2016 at 12:18
  • \$\begingroup\$ 100 or 120 times per second. \$\endgroup\$
    – EM Fields
    Feb 11, 2016 at 14:29
  • \$\begingroup\$ Oops ! Yes indeed ! Let me correct that. \$\endgroup\$ Feb 11, 2016 at 14:31

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.