Volume expander amplifier (T364E)

This circuit was found in the 1961 RCA tube manual. The circuit includes a power supply stage.

Linear Scale Ohmmeter (CB5932E)
Similar circuits can be found on this site. This is from an 80's American documentation. The...
12 V Regulator with Operational Amplifier (CB24824E)
This circuit is from a Radio Electronics magazine from July 1984. The transistor determines the...
General Purpose Meter (CB23573E)
Measuring capacitances and resistance this simple instrument was found in Radio Electronics...