This circuit for incandescent lamps was found in the February 1972 Radio Electronics magazine. The triac is rated according to the lamp power and the sensitivity adjustment is made in R1.
We found this circuit in a 1977 publication for radio amateurs. It serves to test general purpose...
This circuit is from a 1998 Poptronics. The circuit triggers a buzzer after a certain time, waking...
This circuit for electronic voltmeter was found in a publication by Gernsback from 1960. The...