I'm looking for switches to control standard automotive 12v relays. Coil current is about 200 milliamps. I need mom/off/mom in spdt and dpdt. All I find are 125v and 250v switches with various current ratings, 15 to 20 amps.
What is the downside of using these AC rated switches?
Mike
If they're switching only 200 mA they'll be fine.
Ed
"amdx"
** Probably there is none in your example.Switches rated for so many amps at 125 or 250 volts AC are *normally* also suitable for 12 volt and 24 volt DC switching at the same current. Above 24 volts DC, the chance of a sustained arc forming across the contacts upon breaking a circuit becomes very high - switching high current DC requires special techniques.
One proviso is that the load be predominantly resistive - highly inductive loads or loads with high inrush surges like halogen lamps and transformers are special cases.
Relay coils are capable of generating large voltage spikes when de-energised - so it is good practice to place a diode or small cap across the coil to suppress the spike which otherwise can provoke contact arcing.
..... Phil
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