This TTL circuit consists of a frequency divider or converter that has values selected by a switch. The circuit is from Radio Electronics from December 1980 and must be powered by a voltage of 5 V.
With the change of the coil, the circuit can operate at frequencies between 30 MHz and 150 MHz....
The frequency of this Pierce oscillator, found in 1969 documentation, depends on the crystal. The...
This simple circuit can be used to power a simple communication system using ordinary telephones....