This simple timer for incandescent lamps or other non-electronic charges uses a triac as a control element. The triac must be mounted on a heatsink and the time obtained depends on capacitor C2.
This simple oscillator is yet another of the many versions of sonic insect repellent that we find...
The circuit in the figure operates at frequencies from 4 to 20 MHz and also uses a common junction FET...
This TTL counter was found in the April 1979 issue of Radio Electronics magazine. The circuit is...