We found this configuration in a 70s American documentation. The circuit makes use of operational amplifiers of the time. Modern equivalents can be tested.
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...