Found in a 90’s Radio Electronics, this circuit uses a component from the time, difficult to find today. It generates 12 tones in different octaves.
This 1987 signal injector included the power supply from the power grid. The transformer is 6 + 6...
This amplifier was found in a 70s documentation. The product gain x bandwidth is 350 MHz. The...
This simple receiver with junction FET uses a high impedance magnetic earphone (over 2 k). Power...