This power supply uses a Raystor which is a 1964 LDR lamp coupler. The circuit was found in an Electronic Design and the transistor can be replaced with the current equivalent.
This traditional configuration that any Series 139 comparator can use is found in the 1990...
The circuit shown in the figure can be used to detect vibrations or to provide amplified acoustic...
This toy organ was found in Popular Electronics from January 1967. It can be constructed from...