The circuit below was suggested by the Motorola Linear Databook of 1990. The component used is uncommon and the power can be between 7.5 and 12 V.
The sensor is S1 in this alarm that we found in a Radio Electronics magazine from May 1971....
This circuit was found in a 1974 publication. It consists of a voltmeter for high voltages, up to...
Originally suggested by Popular Electronics to control Christmas lights, this circuit can...