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switch rated for dc 100V and dc 10A

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evolive

Newbie level 2
hi. im looking for a switch that is rated for 100v and 10 amps in DC. i am trying to load a power supply with resistors and use switch to activate such load.

i see a lot of AC switches that are rated for 250V and even 20 amps but it is ac. is there a formula that can tell me if it will work for DC?

thank you very much in advance.

Thats a very high grade switch you are after. The reason is that when a switch breaks a circuit, there is an arc (spark) as its contacts part. With AC the voltage goes through zero every 20mS so the arc can never last more then this time. With DC the arc is maintained until the switch contacts have parted wide enough for the voltage not to be enough to jump the gap, so the arc lasts a much longer time. In general a 10A 230V AC switch is rated for 10A 12V DC. That says it all. If you really can't find a switch (that you can afford), use a high voltage power transistor as the main switch and switch the base current instead.
Frank

Hi,

It's to test to make sure that the power supply DC output is working at a certain current. I was thinking even a momentary switch is ok. I've attached an image to maybe explain what the goal is. Do I still need that expensive switch (they are quite expensive) or will I really have to work with a transistor?

Thats a very high grade switch you are after. The reason is that when a switch breaks a circuit, there is an arc (spark) as its contacts part. With AC the voltage goes through zero every 20mS so the arc can never last more then this time. With DC the arc is maintained until the switch contacts have parted wide enough for the voltage not to be enough to jump the gap, so the arc lasts a much longer time. In general a 10A 230V AC switch is rated for 10A 12V DC. That says it all. If you really can't find a switch (that you can afford), use a high voltage power transistor as the main switch and switch the base current instead.
Frank

Try one of these := **broken link removed** (knife switch). They are cheap and repairable. If I were you I would boost the insulation with a few sheets of plastic to stop you accidently touching a live part.
Frank

FvM

FvM

Points: 2
Surprizing but straightforward suggestion. I must confess that I prefer a Tyco/Kilovac vacuum relays for test setups these days, but a basic knife switch would do as well.

I notice they are still manuactured in various forms:

Use this kind of thing....problem solved....

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• 100VDC contact switch.pdf
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