The circuit below is suggested by National Semiconductor in technical documentation on the LM3909. The circuit is powered by a single battery and has a very low consumption.
This 1995 circuit uses interruption sensors or NC connected in series in any quantity. With the...
This circuit, suggested by a 1975 documentation, detects an electrical discharge in a storm by...
Found in an old Electronic Design, this circuit provides an output voltage that is the absolute...