This circuit was obtained from American documentation from the 1990s. The transformer can be a car ignition coil that works like an autotransformer. Q2 must be equipped with a heat sink.
This circuit was found in documentation from the 1980s. It is powered by the audio signal that must...
Damped oscillators can be used to produce sound from percussion instruments such as the triangle, bell,...
Found in Radio Electronics from the 90s, this circuit produces pulses to test an infrared...