Using Transistor as Momentary Switch

[sall]

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!

 

[(*steve*)]

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]

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.

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.

 

[davenn]

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