Good morning,

I am trying to work on some home improvement DIY projects and trying to control light from an RPi / Arduino using USB connection. I've found two possible products, that I think might suit me:




However, I was not really sure how to exactly read the specs for the relays that are given on each website. The light that I am trying to control are going to operating at 12V drawing around 5A (60W bulbs). The specs that are given are:

  • Relay specification: 10A 250VAC/10A 125VAC/10A 30VDC /10A 28VDC
  • Power Supply: 12 VDC
  • Current consumption: 300 mA

Thus I wanted to ask if somebody could enlighten me what the first line "Relay specification" means? Would it be able to handle 5A / 12V bulbs that I would want to connect to it?

Thank you very much to everybody.


1 Answer 1


The "DC30V 10A" means that it can switch DC voltages up to 30V, at currents up to 10A.

Switching DC is more difficult than switching AC, which is why you might see "250VAC 10A" on the same device.

So the basic answer to your question is 'Yes'.

Incandescent light bulbs do draw much more than their rated current when you first turn them on (because they're cold), so your 5A lamp might be quite hard work for the relays. However switches usually struggle more with turning off than turning on, so you'll probably be OK, at least within the margin of confidence you can have in the rating of cheapo relays.


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