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Electronics => Electronics => Topic started by: cooldog on September 27, 2008, 09:02:24 PM

Title: switch that opens when power is applyed
Post by: cooldog on September 27, 2008, 09:02:24 PM

okay so i have been looking around for a switch that when a second voltage is aplyed it opens

lets say i hade a light hooked up and wanted a switch hooked to my usb that turns it on. so when the usb port gives it 3.3v it opens and the light turns on

note: i don't want the usb powering the light

do you guys know of anything like this or how to make it

Title: Re: switch that opens when power is applyed
Post by: Ro-Bot-X on September 28, 2008, 06:11:29 AM

You can use a relay turned on by a transistor or a MOSFET.

Title: Re: switch that opens when power is applyed
Post by: paulstreats on September 28, 2008, 06:12:30 PM

or just use the transistor/mosfet without wasting a relay