We found this circuit in a 1957 Raytheon transistor publication. The circuit can be assembled with more modern transistors with minor changes. The handset must be high impedance magnetic.
This circuit is from a 1987 American publication called Electronics Handbook. The circuit can be...
The indicated circuit performs a slow charge of 12 V batteries maintaining a constant current of...
This ultra-simple circuit need a carbon microphone to operate. The circuit must be powered from D...