This 4-tube circuit was found on a Radio Craft from December 1945. The circuit has excellent sensitivity. Power comes from a power supply with a transformer.
This circuit is from an old 1967 publication. The circuit uses a programmable unijunction...
This simple rhythmic light circuit uses a 110 V to 220 V transformer and can hold a good number of...
The basis of this circuit is a National Semiconductor operational amplifier that functions as a...