Using an LDR as a sensor and an operational amplifier this circuit was found in the Encyclopedia of Electronic Circuits volume 5 from 1995. The circuit triggers an optodiac.
This circuit was obtained from the Radio Electronics magazine of October 1960. The circuit uses a...
Found in an Electronics World of 1966, this circuit makes use of FETs of the time. Modern...
Found in a 90s 303 Circuits, this circuit triggers a load from a 50 mV audio signal. When the...