Using a 4046 PLL we found this circuit in the December 1989 issue of Radio Electronics magazine. The circuit operates at 220kHz, but this frequency can be changed by changing C3.
This circuit can act as a receiver for the transmitter of the previous circuit. We found it in...
This circuit, which can generate voltages up to 25 V, was found in the December 1992 issue of...
Found in a 1966 Electronics World, this circuit applies to the protection of any analog...