We found this circuit in the January 1978 issue of Radio Electronics magazine. The integrated circuit is from that time and is powered by a 9 V battery. The signal must be applied to an amplifier.
Found in a General Electric documentation from the 1980s, this circuit makes use of a FET...
This circuit is based on an MC1408, an integrated circuit that is not common today. The...
Another way to increase the sensitivity of the circuit with the amplification of the sensor...