Direct current motor speed control apparatus

A power control unit capable of delivering high current to a utilizing device, comprising:

• a housing;
• a plurality of field effect transistor pairs;
• a printed circuit board for providing a source circuit for said plurality of transistor pairs;
• a first busbar physically connected to said housing but electrically isolated from said housing to function as a terminal for a positive input and as a heat sink for a freewheeling diode;
• a second busbar connected to the drain heat tab terminals of said plurality of field effect transistor pairs to function as a common drain bus, as a drain input, and an a heat sink for said plurality of field effect transistor pairs;
• a third busbar connected both physically and electrically to said source circuit of said printed circuit board to function as a terminal for the ground connected and as the support for said printed circuit board;
• and
• said first, second, and third busbars being configured to extend beyond both ends of said housing to provide improved versatility in the attachment of said inputs and to provide improved heat dissipation.