This car battery monitor was featured in the January 1988 issue of Radio Electronics magazine. The circuit uses common transistors and has 3 levels of indication made with common LEDs.
This old amplifier, with germanium transistors, was found in a Japanese technical magazine in...
This is the well-known lightning lamp that was published in the March 1988 issue of Saber...
This VFO was found in a 1980s documentation. The central frequency is given by the crystal and the...