Flux capacitor

The flux capacitor was a component of the Doctor's TARDIS. (AUDIO: The Boy That Time Forgot)

Behind the scenes

 * The flux capacitor was the iconic core component of the time machine in the Back to the Future film series.
 * "DeLorean" was written in the Star Wars language Aurebesh next to a drawing of the flux capacitor. (TV: Face the Raven)