We found this circuit in the November 1992 issue of Radio Electronics magazine. The circuit has two integrated circuits, one of which is a preamplifier stage. The power supply must be dual.
This circuit uses incandescent lamps for the 110V or 220V grid. We found this configuration in a 1989...
Found in National Semiconductor documentation from the 1980s, this circuit employs a power...
This circuit was found in Maxim's documentation from the 90's. The circuit provides 12 V x 120 mA....