Using an LDR, this Philips circuit directly activates a relay when light strikes the sensor. The relay is 45 V with 20k coil resistance. The 220 nF capacitor must be polyester for 400 V.
Found in a 1968 documentation, this small amplifier was very popular at the time being used in...
This simple audio signal tracer or follower can be made with a BC548 instead of the original...
According to the 1990 documentation in which we found this circuit, the chickens must be fed at...