Part a of the figure shows an electric fuse with metal having low melting point enclosed in a case with wires leading to the circuit and voltage source. There is a viewing window in the fuse casing. Part b shows a circuit breaker. There is a movable metal strip at one end from which a connector to the circuit is attached at a fixed contact point. There is a compressed spring and switch gear attached adjacent to each other at the other end of the movable metal strip. The movable metallic strip has a bimetallic strip attached perpendicular to it at its center. At the opposite end of the bimetallic strip, there is a connector to the voltage source.