The speed indication of this circuit is made on an analog instrument. The circuit is used to count pulses (rpm) and was found in April 1976 Radio Electronics magazine.
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....