Power feedthrough via C/SUB cb/ in common-emitter class C RF power amplifiers-a commonly believed fallacy

It is suggested that the assumption that the direction of power flow through C/SUB cb/ of the transistor is necessarily from the input-drive source to the amplifier output is a fallacy. Depending on the collector circuit tuning, RF power may be fed to the drive source from the amplifier, or vice versa, or zero RF power may be exchanged through C/SUB cb/. The importance of a correct understanding of this subject is emphasized. It can guide the engineer in designing amplifiers which have higher power gain, higher collector efficiency, more margin of stability against oscillation, and which function properly by design instead of by luck. Circuit operation is explained with reference to experimental voltage and current waveforms.