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.
The Variable Frequency Oscillator (VFO) shown in the figure can generate signals in a frequency range...
The 8038 is an integrated waveform generator (sinusoidal, triangular and rectangular) from...
This circuit was found in a 90s Popular Electronics. The integrated circuit used is uncommon...