ToM Transistor based Extruder “Relay Fix”

This is sort of a derivative work of ToM Extruder Relay Fix by M_G http://www.thingiverse.com/thing:9130
Which is itself a derivative of ToM Extruder Relay Fix http://www.thingiverse.com/thing:5569 by MakeALot http://www.thingiverse.com/MakeALot

This uses transistors instead of Relays. Perhaps some will find this useful if they don’t have access to relays. A variant of the ToM Extruder Relay Fix for dying extruder motors that operates in the forward and reverse directions. This thing uses