The Ampere bridge is a device where two parallel conducting rails are connected to a DC power source, like a battery, and a third conductive object, often roller or a projectile of sorts, makes a short-circuit contact in perpendicular position to the rails. The resulting huge flow of current (Ampere) creates enormous magnetic fields (Lorentz force) which propells the bridgeing object (Bridge) forward. The most well known application is a rail gun. It is often speculated that the explosion like action is over-unity, via a cascade of triggered reactions, and that it can be used for free energy from the environment (aether, neutrinos, plasma ...).