Using a Transistor to power Technic Servo (with PWM)

http://www.philohome.com/motors/motorcomp.htm

I have:
-2x - 5292's
-2x - 47154

I am most likely going to stick with the 47154's because of they consume a fraction of the amount of current - and the amount of power I need them dissipate is minimal.

I am using a VEX 3-pin servo control module (http://www.vexrobotics.com/276-2162.html) to control the servo's. The schematic i posted previously does NOT work as described. I am going to try common emitter.

The point was to remove the stress of powering the servos off of the arduino and power them using a battery or other supply.