This Japanese commercial radio with 5 transistors is from the 60s and is powered by 6 V. It is a conventional superheterodyne configuration with good performance.
This adapter circuit was found in a 1990 documentation. It is possible to connect a telephone line...
The sensor for this alarm is an LDR and it consists of an oscillator that goes into action when...
Found in a 1966’s General Electric documentation, this circuit uses a triple diode from the time....