With this circuit, signals in the range of 10 kHz to 150 kHz can be received at close to 4 MHz from a shortwave receiver. The circuit is from a 303 Circuits from the 90s.
This 1967 Ferranti circuit uses company components. These transistors can be replaced by modern...
This simple thermostat circuit was found in the September 1976 issue of Radio Electronics...
This circuit is from an Electronics World of 1968. The transistors are of the time and the power...