This sensitive circuit was found in the August 1971 issue of Radio Electronics magazine. The SCR is equivalent, and the transistor may be a BC548. The load may be a relay.
Found in the July 1970 Radio Electronics magazine, this circuit has an adjustable activation time...
This circuit was originally suggested in a 1968 publication to generate a white mark (frame) on a...
This circuit was found in a Signetics documentation from the 1980s. Next to the figure are the...