This 40-second delay switch was found in a 1965 Electronic Design. The unijunction transistor might be the 2N2646 and the SCR a sensitive modern equivalent.
Approved by the FCC, this circuit was found in documentation from the 1980s. The circuit uses an...
This circuit can be found in a 1970 Motorola documentation. The circuit can be implemented with general...
This simple 741 circuit was found in the August 1993 Electronics Now magazine. The source must be...