A control circuit for a power converter employing a depletion mode switch and a method of operating the same. The top of the capsule is depressed manually forcing a plunger tube connected to the bottom of the capsule to rip away the bottom and side portion dispensing the material. A sensor may be used to monitor velocity of the diaphragm assemblies. The tubular body with the internal cuff and the external cuff is then removed from the external cuff mold.