How to Calculate the Gain of a PNP Common Collector Amplifier

Many transistor circuits can be used to amplify AC signals. Each terminal on a bipolar junction transistor must be connected electrically to either the input signal source, to DC power or to electrical ground. The grounded transistor lead is said to be connected to the "common" terminal. For example, if the collector lead is connected to electrical ground, the transistor circuit is called a "common-collector" circuit. A common-collector transistor amplifier will not increase the voltage magnitude of an input signal; however, this amplifier will increase the current through the amplifier load.

Instructions

1. • 1

     Write down the value (measured in amps) of the electrical current that will be flowing through the base terminal on the transistor.

   • 2

     Write down the value of the electrical current that will be flowing through the collector terminal on the transistor.

   • 3

     Calculate the transistor gain by using the following formula: Gain = [(Collector current)/(Base current)] + 1. For example, if the current through the collector is 10 milliamps and the current through the base is 2 milliamps, the amplifier will produce a maximum current gain of 6 through the amplifier load.