[SOLVED] Need Help with electronic switch

[dwhildre]

I'm new to this forum and to electronics (sort of).

I'm needing help knowing what to get and hookup in order to make a solid state switch:

Need to complete a ground circuit with max of 10mA on the ground circuit. This will be used in a 15volt dc max as supply (trigger) source. Using this in a car circuit that when ignition is ON it completes the ground in another circuit in a very fast action (I could use a cube relay but they are cumbersome, big, loud, and slow). This circuit could be energized for hours and hours.

Cube relay use to help understand if I'm not asking right question (sorry):
Coil of relay to ignition wire and terminating at the chassis ground, N.O. set of contacts to complete ground circuit when ignition is on.

Sorry, don't know any other way to describe what I need.

I have looked at using NPN's or Mosfets. Stumped.

Thanks in advanced for the help, advice, and understanding.

 

[chuckey]

Get a NPN transistor, at this low current any one will do, connect its emitter to the earth, use the collector to "earth" your new piece of kit. Now if you connect the base to the +12V via a 22K resistor, the transistor will switch on and its collector will fall to about .2V of the earth potential.
Frank

 

[dwhildre]

Chuckey,
Thank you, will give it a try and see how it goes.
Is this the best way to do this or could there be a better way or more appropriate way of doing?

Again, thank you!