This circuit was found in Motorola documentation from 1969. The transistors are from that time. The pulses are 200 ns with 500 mA. Observe the high supply voltage.
This circuit was found in Japanese documentation from the 1960s. It is a commercial circuit with...
This tone control was obtained in the Audio Handbook of the National Semiconductor of 1977. The...
This simple receiver for listening on the phone was obtained in a 1960 documentation. The circuit is...