Additional material:
R1 - 1 k ohm x 1/8 W - resistor
R2 - 100 k ohm x 1/8 W - resistor
P1 - 100 k ohm - potentiometer
B1 - 3 V - 2 small batteries
B2 - 6 V - 4 small batteries
Procedure
In the figure below, we have the arrangement to measure the gain of a transistor.
To use with PNP transistors, simply reverse the polarity of the batteries.
The procedure is simple. We set P1 until the collector current stops increasing (saturation), or stabilizes at 1 mA (many manuals specify the current gains of the transistors for a current of this magnitude).
We then read the corresponding base current on the second instrument (micro-amps). The relationship between the two currents gives us the static current gain of the transistor.
For example, for a base current of 10 uA and a collector current of 1 mA, the gain will be 100.
