This battery-powered 3-valve circuit was found in American documentation from 1947; Two batteries are used, one high voltage and one low voltage for the filaments.
The TPA3100D2 integrated circuit from Texas Instruments (www.ti.com) consists of an efficient...
This circuit was found in a 1965 General Electric publication. The circuit can be adapted to...
This circuit, which combines a bipolar with any JFET, was found in the April 1993 issue of...