This circuit with unijunction transistors was found in a documentation from the 80's. The trigger times of the SCRs depend on the capacitors and are adjusted in the 5M (4M7) potentiometers.
This circuit is a small FM transmitter, capable of carrying its signals over short distances...
This circuit is intended for underwater communications. Of course, the critical point is the...
Originally this circuit excites an incandescent lamp, but it also serves for LEDs, if they use a...