This circuit operates at a voltage of 1.3 V from a single mercury cell. We found in an old documentation and for the components used the frequency is 500 kHz.
This circuit, suggested by National Semiconductor, is a tone control (bass and treble) with high...
This circuit from a Japanese publication in 1968 uses germanium transistors from the time like the...
This circuit is from a publication by Newton C. Braga in the United States. The transistor can be...