A typewriter in which the work of printing or of pressing the type faces against the paper, or printing ribbon, is done by electro-magnetic attraction. The keys close electric circuits, throwing the electro-magnetic action into play. This involves the use of electricity for what is ordinarily only a mechanical process. The strength of the impression, [...]

The ampere-turns on the secondary circuit of an induction coil or transformer. These depend on the path provided for the current. If of negligible inductance, such as a number of incandescent lamps would provide, the ampere-turns should be equal to those of the primary coil. (See Turns, Primary Ampere.)

The ampere-turns in a primary circuit of an induction coil or transformer. In an electric welding transformer, or in the transformer used in the alternating current system, where efficiency is an important element, the ampere-turns in primary and secondary for an efficiency of 100 per cent. should be equal. In the case of an experimental [...]

The rotations of a dynamo armature while it is building itself up or exciting itself. The expression is a bad one, as it is likely to be confounded with the dead turns of armature wire.

An expression applied to the convolutions of wire in a solenoid, electro-magnet, or other apparatus or construction of that kind. A turn indicates a complete encircling of the core or axis of the object. Thus a wire wound five times around a bar gives five turns. While this is its primary meaning the term if [...]

A braid woven of tissue or worsted, and tubular or hollow. Its object is to provide a covering which can be drawn over joints in covered wires. In making the joint the ends of the wires are necessarily bared, and a short piece of tubular braid is used for covering them. It is drawn by [...]

A tube of glass around which is pasted a series of tinfoil circles, diamonds, or little squares, or other form of interrupted conductor. The pieces generally are placed in the line of a spiral. When a static discharge of electricity takes place along the conductor a row of bright sparks is produced at the breaks [...]

In telephone distribution systems, the lines connecting different stations, or different sections of a switch-board and used by anyone requiring such connections; one trunk line answers for a number of subscribers.

A telephone switchboard arranged in sections, which sections are connected by trunk lines, through which trunk lines the desired connections are made.

An apparatus consisting of a vibrating tongue, kept in motion by electricity as in the buzzer, q. v., placed in the small end of a trumpet-shaped tube.