Barney Oliver: Crossover Distortion in Class B Audio Amplifiers

Barney Oliver: Crossover Distortion in Class B Audio Amplifiers

(Image above courtesy of Electronics Tutorials)

This is the famous analysis of class B amplifier cross-over distortion by the then head of HP Reasearch Labs, Dr. Barney Oliver,  published in the February 1971 edition of the HP Journal.  The ideal bias current Iq for a class B emitter follower amplifier is approximately  Iq = .026/(Re+re+(rb/hFE)) – the ideal value ending up somewhere between a 13 to 26mV drop across the output transistor emitter degeneration resistors.  This paper provies the theoretical underpinings for that relationship. So, when you hear about the ‘Oliver’ voltage, you know where it came from. You can read more about Barney Oliver here and here

Download the PDF here:  Cross Over Distortion in Class B Amplifiers

See the comments below. My practical experience over many amplifier builds is that indeed somewhere  13 and 26 mV  is ideal.