Potential Energy

That form of force, which, when liberated, does or performs work.

Power Unit

The volt-amperes or watt.


The induction coil in induction machines, or in a transformer.

Push Button

A thumb piece which serves as a switch to close a circuit while being pressed inwardly.


Such arrangement of electrical connections which give off the largest amount of current.


An instrument in telephony and telegraphy which receives or takes in the sound or impulses.


The device which opens or closes a circuit so as to admit a new current which is sent to a more distant point.

Repulsion, Electric

That tendency in bodies to repel each other when similarly charged.


The springing back to its former condition or position. Electricity has resilience.


The quality in all conductors to oppose the passage of a current.

Resistance Coil

A coil made up of wire which prevents the passage of a current to a greater or less degree.

Resistance, Electrolytic

The counter force in an electrolyte which seeks to prevent a decomposing current to pass through it.

Resistance: Internal, External

The opposing force to the movement of a current which is in the cell or generator. This is called the internal. That opposite action outside of the cell or generator is the external.

Resonator, Electric

An open-circuited conductor for electrically resounding or giving back a vibration, usually exhibited by means of a spark.


A device which has an adjustable resistance, so arranged that while adjusting the same the circuit will not be open.

Safety Fuse

A piece of fusible metal of such resistance that it breaks down at a certain current strength.


When a liquid has taken up a soluble material to the fullest extent it is then completely saturated.


One of the two coils in a transformer, or induction coil.

Secondary Plates

The brown or deep red plates in a storage battery when charged.


Producing electricity by its own current.


Arranged in regular order. From one to the other directly. If lamps, for instance, should be arranged in circuit on a single wire, they would be in series.

Series, Multiple

When lamps are grouped in sets in parallel, and these sets are then connected up in series.

Series Windings

A generator or motor wound in such a manner that one of the commutator brush connections is joined to the field magnet winding, and the other end of the magnet winding joined to the outer circuit.


Going around.

Shunt Winding

A dynamo in which the field winding is parallel with the winding of the armature.