This circuit was found in a 1968 documentation. It makes use of both NO and NC reed-switches and small magnets attached to a card in the form that results in the drive combination.
We find this circuit in a 1980s documentation. The circuit uses uncommon components today which can...
We found this circuit in a 1977 Radio Shack documentation. The circuit should be powered, for...
With the circuit shown in the figure it is possible to digitally control the gain of an...