Variable speed trigger converted to variable speed knob

[johnwnixon]

site:www.edaboard.com in5404

I have what should hopefully be a simple question. Please forgive my ignorance, my knowledge in this arena is limited.

I have a trigger from a variable speed powered screw driver that I want to replace with a knob that will control the speed of the motor. The screwdriver is 12VDC. The trigger has a rectifier (IN5404) and a transistor? which is labelled:
P75NF 75 @
75 AFV V6
PHL 625

The transistor is glued to a heat sink.

I would like help with two things -
1.) Locating the correct sized potentiometer (or do I need a rheostat?).
2.) How to wire the new pot with the existing components I have to make an effective variable speed control.

Thanks for any help you can provide this novice!

John Nixon

 

[johnwnixon]

Here's an update. That thing I was calling a transistor is a really a power mosfet

The datasheet can be found here:
**broken link removed**

So I have a power mosfet, a rectifier a 12VDC power source and a desire to make a variable speed control knob.

Can anyone point me in the right direction?

Thanks,
John Nixon