Page 167 - Complete Wireless Design
P. 167
Amplifier Design
166 Chapter Three
For bipolar transistors, Class C amplifiers permit the use of three biasing
techniques: signal, external, and self-bias. Nonetheless, the average Class C
transistor amplifier is normally not given any bias whatsoever (Fig. 3.67), but
in order to lower the chances of any BJT power device instability, the base
should also be grounded through a low-Q choke, with a ferrite bead on the base
lead’s grounded end (Fig. 3.68). All of these biasing techniques will still require
Figure 3.67 A Class C amplifier showing lack of bias.
Figure 3.68 Class C power amplifier with ferrite bead on
ground end of base lead.
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