Abstract: A method for determining motional branch current in an ultrasonic transducer of an ultrasonic surgical device over multiple frequencies of a transducer drive signal. The method may comprise, at each of a plurality of frequencies of the transducer drive signal, oversampling a current and voltage of the transducer drive signal, receiving, by a processor, the current and voltage samples, and determining, by the processor, the motional branch current based on the current and voltage samples, a static capacitance of the ultrasonic transducer and the frequency of the transducer drive signal.

Abstract: Test circuits on heater chips for testing a heater circuit having a heater element and a first power device. The test circuit can include a second power device, a test device configured to hold the first power device off and the second power device on for a selected heater circuit when the test device receives a signal to activate the test circuit, and a common test output to transmit a signal indicative of a state of the selected heater circuit. Methods for using the same are also provided.

Abstract: A spring formed from strip steel crimped on a threaded bolt for receiving a threaded member preferably having four arms separated by 90 degrees to form a cross and wherein the ends of the legs are cambered in order to provide greater bearing surface against each of the two walls of a corner in a tubular member when the spring member is inserted into the tubular member. Where the arms extend from the well of the spring, the arms are slightly notched in order to provide for automatic indexing. When the spring is compressed the wells formed by the spring contact the walls of the tubular member.