Found in a 1970 documentation, this circuit makes use of 741 operational amplifiers that are common today. Note that the power supply must be symmetrical.
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....