This SCR relaxation oscillator was found in an 80's Electronic Design. It flashes a small incandescent lamp in frequency that depends on the capacitor.
This circuit can be used as a noise canceller for communication receivers or even common ones. The...
This modulator can be used in a data link or other signals up to 200 kHz. Range can be achieced...
Suggested by a Popular Electronics from the 90s, this circuit triggers an external load, relay or...