This 80's General Electric circuit is guarded by the noise-guard for operating current. The circuit has an input sensitivity of 3 pA. The font must be symmetrical.
This circuit makes use of a special LM195 power transistor not very easy to obtain. The circuit is from...
Found in documentation from the 90s, this circuit can employ other comparators in the series such as...
Suggested by Philips in a 1970 publication, this circuit uses components from that time. No...