These optical relays, which can act as a shield, were found in an American documentation from the 1980s. The circuit has a LDR sensor. It can be adapted for other types of sensors.
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...