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Using Transistor as Momentary Switch

sall

Jan 29, 2010
51
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Jan 29, 2010
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I am trying to figure out how to use a transistor to operate as a momentary switch. Right now I am using a relay, a cap and a resistor. I would just like to be able to make the circuit a bit smaller than using a relay.

TIA! :D
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
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25,510
OK, so you need to explain more.

What will cause this "switch " to close?

Do you want it to stay closed for a brief period then open again?

What is this period?

What is the load that you are controlling?
 

sall

Jan 29, 2010
51
Joined
Jan 29, 2010
Messages
51
Yes, I apologize for the lack of information and hasty post. I have a relay setup so that it receives signal from 12V switched wiring in my vehicle and in turn acts as a momentary switch to power on my laptop any time the ignition is in accessories/run.


attachment.php

I would like to do something similar with a transistor if possible to reduce the size of the circuit, but am unsure how to accomplish. I am planning on combining this along with other small circuits on one board for a carpc project.
 

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davenn

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Sep 5, 2009
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by the time you have a transistor or 2 and associated components on a cct board and then mount that board in an insulated case its probably going to end up being bigger in size than the relay system you are currently using.

Dave
 
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