Electronic – Can a high voltage rated push-button switch be used on lower voltages

power electronicsswitches

I have a question regarding switch usage in a high voltage, very low current circuit (micro amps). Basically, we're taking the 120VAC out of the wall, converting it to DC (output can be either 5, 12, 15 or 24VDC) where it's going to a switch that is going to be the input to an SEL relay. Currently, it uses 120VDC as the input. What I want to know is can a push button with this high of a rating be used for a low voltage application? There are microamps going through so the power dissipated is <1W. Everything I've been taught tells me a push button will work regardless of the voltage running through it, as long as it's pushed (and the button switch isn't melted).

The button I'm referring to

Best Answer

You have to observe the minimum current and voltage for the switch.

Typically mechanical contacts aren't gold-plated so a thin oxide layer will build up with time and it needs some amount of energy to "burn" that thin layer. See https://en.wikipedia.org/wiki/Wetting_current

A capacitator to generate some inrush current may help but this depends on your setup. If this is a home project and reliability isn't essential just use the switch...