This 4-channel mixer amplifier was found in an American publication from 1947. The circuit uses counterphase output tubes and a transformer power source.
The power of this converter is not the greatest, it can only supply small fluorescent lamps,...
This circuit is in the very datasheet of Texas Instruments that manufactures the component...
Found in a PE Hobbyst Handbook from 1991, this circuit uses a common photocell as a sensor. The...