I just started working with/reading about solid state relays last week, so bear with me here.

I have an air compressor -- 120 V | 60 Hz | 2.8 A -- that I would like to operate with a control signal from an Arduino (to turn on the SSR to power the compressor).

The input voltage is 115 VAC from a line filter -- at 115/250 VAC, you get 10 A rms max. The AC voltage after the filter will also be converted to 24 V, DC (via an open-frame power supply). This 24V will power a myriad of other components (I can provide a list if necessary).

In certain scenarios, the compressor will run along with the 24V DC-supplied components.

Given these parameters, what should I look for in an SSR?
What kind of tolerances need to be taken into account with respect to making the SSR work properly or damaging it?

Thanks for any info you can provide.



1 Answer 1


Finding a suitable SSR should be fairly easy based on your requirements. Look on amazon, ebay, and automation direct for reasonably priced options.


  1. Input voltage, and DC or AC. You want DC. Most DC ssrs have a huge input voltage range like 3-60v or similar.
  2. AC or DC output. You want AC.

  3. Zero crossing or not. This only applies to AC output SSRs. Just get zero crossing unless you know otherwise. Zero crossing minimizes the heat generated during switching by waiting for the AC voltage to hit 0 to switch. The only time you don't want this is if you're creating some kind of wave chopping dimmer circuit.

  4. Current rating. High current SSRs are cheap, so give yourself some margin.
  • \$\begingroup\$ Hey Drew, thanks for the reply. With a compressor rated at 120VAC, what kind of margin should I allow for the output of the SSR? Also, would 10A be reasonable for a 2.8A compressor? Thanks \$\endgroup\$ Sep 9, 2019 at 15:13
  • \$\begingroup\$ A name brand SSR might have a surge rating, but your compressor probably doesn't state the surge current anyway. So you'll probably have to just try it and see. If it were me I'd probably just spend the extra 2 bucks and get a 25 or 40A version and call it done. \$\endgroup\$
    – Drew
    Sep 10, 2019 at 3:33

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