This circuit can generate signals of different frequencies, switched by a DC voltage. The frequencies are determined by the crystals. The circuit is from a 90s American documentation.
The frequency of this Pierce oscillator, found in 1969 documentation, depends on the crystal. The...
This circuit is based on a regulator component that consists of a transistor and zener in the same...
This circuit is from a 1965 General Electric publication. It uses a thermistor to fire a reed...