This conventional relay light detector circuit uses a 741 as a voltage comparator. The sensitivity adjustment is made in R1. The supply voltage depends on the relay used.
Published in 1988 in Hands-On Electronics, this circuit converts the 12 V of a battery into 120 V...
This circuit was found in an American technical manual from the 1980s. The LM111 is an uncommon...
This circuit was obtained in an American publication of the time. Transistors are commonly used. The...