This circuit is intended for underwater communications. Of course, the critical point is the shielding to avoid water. The circuit is from an Electronic Hobbysts Handbook from the 90s.
This non-regulated power supply uses a single secondary winding transformer. The secondary voltage...
Using a small incandescent bulb as a regulator, this Wien bridge oscillator produces a sinusoidal...
The figure presents a configuration that can be very useful for audio equipment designers. What...