The blade carries a small electrical charge. This charge is continuously monitored by a digital signal processor. When contact is made, the human body absorbs some of the charge, causing the voltage to drop. The drop in voltage triggers a quick release aluminum brake. A heavy duty spring forces the brake into the teeth of the spinning blade. The teeth dig into the aluminum, stopping the blade cold. The blade's momentum forces it to retract below the table, and the motor is automatically shut off.