“Instead of a conventional linear power supply, Holt built one like those used in oscilloscopes. It switched the power on and off not sixty times per second, bu

“Instead of a conventional linear power supply, Holt built one like those used in oscilloscopes. It switched the power on and off not sixty times per second, but thousands of times; this allowed it to store the power for far less time, and thus throw off less heat.” Not exactly, the power is stored in an inductor and fed to the load, the inductor being topped-up by switching the unregulated rail on-and-off thousands of times a second.