Inventors:
Richard H. Morrow - Temple PA
Grant F. Stetzler - Temple PA
Assignee:
Western Electric Company, Inc. - New York NY
International Classification:
G01R 3122
Abstract:
In testing transistor devices, measurements of the collector-emitter leakage current of the devices with the base open (i. e. , I. sub. CEO) generally require long measuring intervals. This is due to the necessity of charging the Miller Capacitance of the device under test prior to taking the measurement. While the Miller Capacitance is charging, a small base current flows which makes an accurate reading of the I. sub. CEO very difficult. To shorten these measurement times, a voltage is applied to the base of the device to increase the charging rate of the Miller Capacitance. After a predetermined time, the voltage is disconnected thereby opening the base of the transistor device. The I. sub. CEO reading is then taken at the emitter of the device after it has stabilized to an approximate level of I. sub. CEO. As an alternative to the application of a voltage to the base, a feedback circuit is connected between the emitter and the base of the test device to provide an automatically adjusted driving current to the base.