GB993660A - Apparatus for measuring the high frequency current amplification factor of transistors - Google Patents

Abstract

993, 660. Measuring transistor characteristics. S. YAGYU. Aug. 24, 1962 [Aug. 31, 1961], No. 32584/62. Heading G1U. An apparatus consisting of the circuits 1-4 for measuring the high frequency current amplification factor and load characteristics of a transistor Tr includes a high frequency oscillator circuit 1 which comprises an oscillator OSC connected through a condenser C 1 and resistor R 1 to the base of the transistor, the base also being connected through an inductance L 1 to ground. The emitter of the transistor is connected through a resistor Re to a bias source of pulsating current E e , and is grounded through an emitter condenser C 2 , these components forming part 2 of the apparatus. The collector of the transistor is connected via a collector circuit 3 to an observation circuit 4 wherein the output from the collector circuit is applied through an amplifier A along one deflection axis of an oscilloscope B, and the potential from the bias source Ee is applied along the other deflection axis. The collector circuit 3 includes a serially connected collector inductance L 2 , a switch S shunted by a load resistor R L and a variable voltage source E c . The test arrangement, by using a pulsating emitter bias current provided from the source E e , eliminates the need for adjustment of the bias current and recalibration of the apparatus for different transistors. With the switch S closed the relation between current amplification factor and emitter current at the high frequency provided by the oscillator OSC is indicated on the oscilloscope, whilst with the switch open a load characteristic may be shown directly. By adjusting the voltage source E c the variation of the characteristics under different operating conditions of the transistor may be indicated.