AVR-Chat

I may have posed this question some time ago, but I'm still confused.  I'm
trying to determine if a pcb slide switch will meet my current requirements,
which in this particular case are 200 mA at 12 VDC.   So I'm looking at a
page (1646) of the Mouser catalog, for such switches all from the same
manufacturer (Alcoswitch) and I see one series that says:

"gold, 0.4 VA; silver 300 mA @ 115 VAC"

So if I divide 0.4 VA by 12 V I get 33 mA.  How come this seems so
drastically less than 300 mA at 115 VAC (300 mA x 115 V = 34.5 VA)?  I know
there is an AC/DC thing here but the difference in this "power" is almost
two orders of magnitude!

Another series is similar:

"gold, 0.4 VA @ 20 VDC; silver 300 mA @ 115 VAC"

Why was the "@ 20 VDC" added here?  How do I convert the rating to my 12 VDC
level?

Then another series says only:

"300 mA @ 125 VAC"

Does that mean the switch is not usable with DC?

These seem like incredibly stupid and elementary questions to be posing
here, but it's driving me nuts.  Can somebody help me out, please?  My
intuition tells me a switch that can take 300 mA at 115 VAC ought to be able
to handle 200 mA at 12 VDC.

Thanks, Steve


 

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