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Audio-Frequency Class B Power Amplifiers

If the definition of a class B amplifier is examined, it is apparent that the output of a tube will be as given by equation 1 and as shown in Fig. 9. Thus, the first alternating term will be the signal to be amplified, and for two push-pull tubes these will add, as can be demonstrated by a graphical analysis.12 The output wave will contain, however, a series of even harmonic terms, and an analysis will show that these are suppressed in the primary of the output transformer. Thus, two tubes in a balanced circuit must be used. In such amplifiers the grids usually are driven positive, grid current flows, and grid-driving power must be supplied.



Last Update: 2011-05-19