This circuit was found in the 1991 Electronics Experimenters handbook. It can be used to display RGB signals on old NTSC televisions.
This 1989 circuit uses a gas sensor from the era, which is hard to find these days. The circuit...
This circuit is from an old publication from the 1950s. The circuit uses germanium transistors but can be...
We found this circuit in a 1965 publication by General Electric. The zener is 8.2 V x 1 W and the...