We found this cable tester in a Popular Electronics from the 90s. The circuit uses a connector according to the cable to be tested. Adaptations can be made for different types of cables.
This simple 1 transistor circuit was found in an American documentation from the 60's. The...
Found in a magazine 73 for radio amateurs, this circuit makes use of general purpose transistors and...
The presented circuit allows to control the valve of a tap. The positioning of the emitter and the...