Found in a 1970 American publication, this circuit uses transistors of the time. These transistors may be replaced by current equivalents. The factor Q is greater than 3 000.
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...