Technology Everysecond » emitter http://mnunioni.org seabloggers INC Fri, 03 Sep 2010 03:41:58 +0000 en hourly 1 Classification of Power Amplifiers http://mnunioni.org/2009/09/11/classification-of-power-amplifiers/ http://mnunioni.org/2009/09/11/classification-of-power-amplifiers/#comments Fri, 11 Sep 2009 10:23:13 +0000 admin http://mnunioni.org/?p=653 For an amplifier, a quiescent operating point (Q point) is fixed by selecting the proper d.c biasing to the transistors used. The quiescent operating point is shown the load line, which is plotted on the output characteristics of the transistor. The position of the quiescent point on the load line decides the class of operation of the power amplifier.

The various classes of the power amplifiers are

Class A
Class B
Class C
Class AB
Before defining the position of the quiescent point on the load line, for the various classes. The characteristics curves are plotted for various values of base current. The intersection of the output characteristics curve and a load line is the operating point. The point is fixed for a transistor called quiescent point or Q point.

The collector current varies above and below its quiescent value, in phase with the base current. The collector to emitter voltage varies above and below its quiescent value, 180 degree out of phase with base current.

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