Found in a 90s documentation, this circuit makes use of D1, a switching diode that is uncommon today. D3 is an LED. The circuit monitors 12 V batteries.
This circuit has been found in an old documentation, but can be used as input shield for current...
This circuit generates signals from 0.01 Hz to 10 kHz, but uses unusual components today. The...
This circuit was found in the June 1969 issue of Radio Electronics magazine. The circuit uses a...