This amplifier with old germanium transistors is from a 1957 documentation. The power is a few hundred milliwatts and the transformers are common types of driver and output of the time.
Frequencies from 1 to 10 MHz can be obtained with a small adjustment of the variable in a narrow...
Pressing and releasing S, the capacitor C1 charges and discharge slowly through the oscillator...
This Wien bridge oscillator was found in Radio Electronics from the 90s. The circuit uses the 741...