Bobbin. A spool of wood or other non-conducting substance wound with insulated wire. In a tangent galvanometer the bobbin becomes a ring with a channel to receive the wire.
Boiling. In secondary, or storage, batteries the escaping of hydrogen and oxygen gases, when the battery is fully charged, resembles water boiling.
Bonded Rails. Rails used in an electric traction system, and which are linked or connected together to form a perfect circuit. Used principally in the third-rail system.
Brake, Electro-magnetic. A brake to stop the wheels of a moving car. It consists of a shoe, or ring, which by magnetic force is drawn against a rotating wheel to stop its revolution.
Branch. A conductor which leads off from a main line to distribute current locally.
Brassing. A process of electro-depositing brass in a bath containing both copper and zinc. A plate of brass is used as an anode.
Brazing, Electric. A process in which the spelter is melted by electric current, so that the two parts are united as one.
Break. A point where an electric conductor is broken, as by a switch or a cut-out.
Bridge. A special bar of copper connecting the dynamos with the bus wire in electric lighting or power stations.
Bronzing. The deposition of bronze by electro-plating methods. The mixture is of copper and tin, and a cast bronze plate is used as an anode.