TC 9-62
TRANSISTOR CONFIGURATIONS
2-61. A transistor may be connected in any one of three basic configurations (see also
Figure 2-18):
Common emitter.
Common base.
Common collector.
The term "common" is used to denote the element that is common to both input and output
circuits. Since the common element is often grounded, these configurations are frequently
referred to as grounded emitter, grounded base, and grounded collector.
Figure 2-18. Transistor Configurations
2-62. Each configuration has certain characteristics that make it suitable for specific
applications. An easy way to identify a specific transistor configuration is to follow three
simple steps:
Step One - Identify the element (emitter, base, or collector) to which the input
signal is applied.
Step Two - Identify the element (emitter, base, or collector) from which the
output signal is taken.
Step Three - The remaining element is the common element, which gives the
configuration its name.
By applying these three simple steps to the circuit in Figure 2-14, we can conclude that this
circuit is more than just a basic transistor amplifier; it is a CE amplifier.
2-20
TC 9-62
23 June 2005
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