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 provides an accurate measure of the internal resistance of an analog instrument. Just...
The CMOS oscillator illustrated in the figure has a frequency that depends on the temperature...
This circuit uses an unusual integrated today. It fires when the voltage exceeds 13.6 V in a...