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Switch design with MOSFETs

Sigmoid

Jul 21, 2013
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Jul 21, 2013
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Hey,

I'm trying to figure out the principles of using MOSFETs as simple on-off switches.

The intended function of this design is to convert a standard, garden variety three terminal ON/OFF/ON switch into an incremental (zero/one/two) switch.

At one extremity (A on) no lights are on. In the middle (off) position the right light comes on. In the top (B on) position both lights are lit.

mosfet.png

Did I get MOSFETs right? Or would there be a better way of solving this? Are the megohm resistors a good choice?
 
Last edited:

duke37

Jan 9, 2011
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Megohm resistors are OK.

Just make sure that the FETs can stand 24V on their gates with some leeway.
 

BobK

Jan 5, 2010
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I would go with lower resistors, more like 10K for more immunity to noise.

Bob
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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And for faster switching speed
 
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