Automatic Cut-out

A device which acts through the operation of the mechanism with which it is connected. It is usually applied to a device which cuts out a current when it overcharges or overloads the wire.


In electroplating, the vessel or tank which holds the electroplating solution.


A combination of two or more cells.

Battery, Dry

A primary battery in which the electrolyte is made in a solid form.

Battery, Galvanic

A battery which is better known by the name of the Voltaic Pile, made up of zinc and copper plates which alternate, and with a layer of acidulated paper between each pair of plates.

Battery, Storage

A battery which accumulates electricity generated by a primary battery or a generator.


A term applied to the conducting medium that bears against the cylindrical surface of a commutator.


An electric call produced by a rapidly moving armature of an electro-magnet.


A number of wires or conductors assembled in one strand.


The amount of light given by the legal-standard candle. This standard is a sperm candle, which burns two grains a minute.


The carrying power of a wire or circuit, without heating. When heated there is an overload, or the capacity of the wire is overtaxed.

Capacity, Storage

The quantity of electricity in a secondary battery when fully charged, usually reckoned in ampere hours.


A material, like coke, ground or crushed, and formed into sticks or plates by molding or compression. It requires a high heat to melt or burn, and is used as electrodes for arc lamps and for battery elements. It has poor conductivity, and for arc lamps is coated with copper to increase its conductivity.

Cell, Electrolytic

A vessel containing an electrolyte for electroplating purposes.


The quantity of electricity on the surface of a body or conductor.

Chemical Change

When a current passes through electrodes in a solution, a change takes place which is chemical in its character. Adding sulphuric acid to water produces heat. If electrodes of opposite polarity are placed in such an acid solution, a chemical change is produced, which is transformed into electricity.

Choking Coil

An instrument in a circuit which by a form of resistance regulates the flow of the current, or returns part of it to the source of its generation.

Counter-electromotive Force

Cells which are inserted in opposition to a battery to reduce high voltage.

Circuit, Astatic

A circuit in an instrument so wound that the earth's magnetism will not affect it.

Circuit Breaker

Any instrument in a circuit which cuts out or interrupts the flow of a current.