A easy to build and use H-Bridge for DC motors.  Uses 4 NPN type PN2222A standard transistors

We are using this module on a 7.4 volt system, tested working on 5 and 3.3 volt systems also.

 

Trigger inputs cannot be a PWM source for speed control.  Add a NPN switch to the Negative return to use for PWM.

 

The Ground of this unit should be connected to the common project ground.