This circuit is from a 1967 Triplett manual. The circuit uses components of the time, the common FET and the general-purpose bipolar transistor.
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...