Double button microphone preamp (T352E)

This circuit was obtained in the 1937 RCA tube manual. Tubes are well known types that can even be obtained today. The power source is not given.

Common Power Supply Circuit Bridge (CB6070E)
This circuit was suggested by Siliconix in a 1980s publication. The circuit uses components from the time...
Remote Control Transmitter (CB469)
This continuous wave transmitter (CW) can send signals in the 30 to 100 MHz band, depending on the...
High Power Sound and Ultrasonic Generator (CB1563E)
In the figure we show an application in which the 4093 excites a stage with 4 transistors in the...