We found this circuit in the Radio Electronics magazine of February 1993. The main integrated circuit is from that time and the power supply is made with voltages of 6 to 15 V.
The search coil of this detector consists of 140 turns of wire 18 in an 8 inch diameter form. The...
This circuit was found in a 1989 documentation and was intended to be part of a presence...
In the figure we show a configuration for a crystal controlled overtone oscillator using a...