This circuit of dozens of watts uses germanium transistors and the critical components are transformers. The circuit is from the 1960 Mullard transistor application manual.
This circuit can generate signals up to 100 kHz. Found in documentation from the 1980s, it makes...
Some old record players use variable reluctance phono pickups, requiring a special amplifier...
This circuit is from a Radio Electronics from July 1965. The circuit uses components from the time...