Obtained from a 1969 documentation, this circuit can operate at frequencies up to 500 Hz, counting up to 999. The circuit makes use of neon lamps of the time.
The ZN414 integrated circuit consists of a complete radio from the 1980s. This single receiver...
The circuit shown in the figure uses a programmable unijunction transistor (PUT) of the BRY39 type...
This 1970s RCA circuit can be triggered by light or dark, depending on how the LDR is connected....