The flux capacitor, which consisted of a regularly squared compartment with three flashing lights (arranged in a “Y” configuration), was described by Doc as “what makes time travel possible”. The device is the core component of the time machine.
The device was located between the headrests of the seats and, as the time machine neared 88 mph, light coming from the flux capacitor pulsed more rapidly until it became a steady stream. Doc originally conceived the idea for the flux capacitor on November 5, 1955 when he slipped and hit his head on his bathroom sink while standing on the toilet to hang a clock. A flux capacitor is also seen in the front of Doc’s second time machine, the Jules Verne train, at the end of Back to the Future Part III.
A flux capacitor appeared in Back to the Future: The Ride at various Universal Studios theme parks. After the closing of Back to the Future: The Ride Doc can still be seen riding around on a bike, complete with its own flux capacitor.
Although the films do not describe exactly how the flux capacitor works, Doc mentions at one point that the stainless steel body of the DeLorean has a direct and influential effect on the “flux dispersal”, but he is interrupted before he can finish the explanation. The flux capacitor requires 1.21 Gigawatts of electrical power to operate. In the instruction manual for the AMT/ERTL Delorean model kit it says: “Because the car’s stainless steel body improves the flux dispersal generated by the flux capacitor, and this in turn allows the vehicle smooth passage through the space time continuum.”[verification needed]