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.
The existence of field effect transistors at the input of the integrated circuit (operational...
This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms...
This circuit was found in a Popular Electronics from 1991. The transistor could be the BC548. The...