Found in American documentation from the 90's, this JFET stage has an input impedance of 500 M ohms. Bipolar transistors are general purpose types and the FET supports an equivalent.
This circuit was published in the Radio Electronics magazine of September 1950. The transistors are from...
This transistor amplifier provides 35 W of power to an 8 ohms speaker and must be powered by a 59...
This circuit was suggested by Siliconix in a 1980s publication. The circuit uses components from the time...