Flux Capacitor

The flux capacitor was developed by Emmett Brown after he hit his head and had a flash of inspiration. When connected to a vehicle that moves at 88 miles per hour, a fully-charged flux capacitor is capable of transporting that vehicle through time.

It originally required plutonium for fuel, but was later shown to run off sources as advanced as fusion and as primitive as steam. The capacitor was equipped onto Brown's DeLorean and the train time machine he built after 1885.