This circuit was found in a 1964 documentation. It shows how to achieve automatic gain control for an oscillator. The transistors are of the time and the circuit controls signals from 2.6 to 3.1 kHz.
This circuit can be used as a source of signals for generators of different types, sirens, or...
This circuit is based on a 5 V LED flasher. We found it in October 1980 Radio Electronics...
This interesting circuit in which the LED display is circular imitating a common clock appeared in the...