i have a s202s01 relay that i want to connect to my microcontroller. The problem is that the load i want to control is a DC source. Is there any way to make that ssr (3-24dc, 8A 250VAC) work with a 12v 0.5A DC load?

I haven't tried anything yet because i don't want to damage it.


You need to choose something suitable for DC.

Your relay has a Triac output. The problem is that in order for a Triac to turn off, the current must drop to near zero. For AC, that would happen every half-cycle; but for DC that would likely require turning off the DC supply.

12V @ 0.5A is a pretty simple requirement. For a low-side switch, an N-channel MOSFET would work nicely, although if your load is inductive, you will also need a flyback diode.

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  • \$\begingroup\$ I could turn the dc source off for a moment and start it again with a second ssr. That would work without any damage? \$\endgroup\$ – Sinjuice Mar 9 '15 at 14:29
  • \$\begingroup\$ That sounds silly to me. It would be a pain. You could probably do that, but then why not choose an SSR designed for DC? The right tool for the right job. \$\endgroup\$ – Tut Mar 9 '15 at 14:33
  • \$\begingroup\$ Because of the cost, i already have the AC ssr, and at the local electronic store it costs me 20+ euros one ssr for DC. I know is not the best way to do it, but is the cheapest. And is not about turning on and off the DC source, is changing between 2 voltages that that source provides. \$\endgroup\$ – Sinjuice Mar 9 '15 at 14:34
  • \$\begingroup\$ "I could turn the dc source off for a moment and start it again with a second ssr" ... So long as the second SSR is connected to the AC input of a 12VDC supply. If it is connected to DC such as with a battery, you still have the same problem of turning it off. \$\endgroup\$ – Tut Mar 9 '15 at 14:44
  • \$\begingroup\$ About the N-Channel MOSFET, it would work with a 3.3v on the gate at full capacity? \$\endgroup\$ – Sinjuice Mar 9 '15 at 14:45

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