While troubleshooting the power supply of a 1970s Centurion system, [Usagi Electrics] came across a fascinating feature of these units: the ferroresonant, or constant voltage transformer (CVT).

The diagram below shows the main features of the ... This means that high currents waste more energy than low currents. When a transformer steps up voltage, current is stepped down.

“Electromagnetism” is a silent educational film from the late 1920s that explains the basic principles of electromagnetism using simple animations, diagrams, and live-action demonstrations.