General Electric suggests this circuit in an 80's documentation. The circuit makes use of PUTs that are not common components today. Note the timing components that may change.
The figure shows a Wien Bridge circuit with non-linear feedback. The resistance of the RL lamp is...
This commercial medium and short-wave radio was manufactured in Japan in the 60s. The circuit has...
The energy that powers this radio's amplifier circuit is obtained from the signal itself. The coil...