Electric Foil Tip Diagram

In order to score a valid touch in electric foil, the point must be depressed on the opponent's lamé. This does two things simultaneously: it breaks the electrical circuit which flows through the insulated wire and back into the weapon itself, and it completes a circuit through the opponent's lamé and back to the scoring box. This is how the machine knows that you have made a valid touch. An "off-target" touch is made when the foil circuit is broken without completion of the lamé circuit. If the lamé circuit is completed but the foil circuit is not interrupted, then no light comes on, unless it is due to your opponent's timely riposte. Normally, this is what happens when: a) your distance was just short. b) your attack was flat (such as a badly executed "flick"). c) your opponent is keeping perfect distance. d) your weapon has shorted to itself, in which case it will not hit on or off target.

Diagram by Dave Redburn