We found this circuit in the October 1996 Electronics Now magazine. The circuit uses LDRs as sensors and drives relays. The relays must have voltages according to the power supply.
We found this circuit in a 90's EDN. The circuit is based on a control integrated that is still...
In the figure we have the way to use the transistors of an old-paired pair as a trigger circuit. The...
This very high input impedance JFET circuit was found in the 1995 Encyclopedia of Electronic...