Found in a 1965 Radio Shack documentation this oscillator can be used with modern general purpose transistors like the BC558. The transformer is the output type for transistor radios.
This mixer uses only four passive component and can be used with high impedance sources. The input and...
This circuit was found in a Popular Electronics of the 90s. The resistor R4 determines the load...
This circuit was found in an American 1980s documentation. The transistors admit equivalents and the...