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A current which periodically changes or reverses its direction of flow.

An electric generator or dynamo for producing alternating currents.

of an electrical current; an attachment to certain electrical machines, by means of which alternating currents are made to be continuous or to have the same direction.

To put out of phase, as two parts of a single alternating current.

A current flowing in one direction only; -- distinguished from alternating current. When steady and not pulsating a direct current is often called a continuous current.

An increase in the ratio of transformation of an alternating current converter, accompanied by other changes in electrical conditions, occurring when the secondary of the converter is connected with a condenser of moderate capacity; -- so called because first observed in connection with the Ferranti cables in London.…

The apparent resistance in an electric circuit to the flow of an alternating current, analogous to the actual electrical resistance to a direct current, being the ratio of electromotive force to the current. It is equal to R2 + X2, where R = ohmic resistance, X = reactance. For an inductive circuit, X = 2pfL, where f =…

nt for autographically recording the wave forms of varying currents, esp. rapidly varying alternating currents.

stationary commutator and rotating brushes, in which the exciting field is induced by the alternating current in a short-circuited magnetic core instead of being produced by an external magnet.

A machine for converting an alternating current into an alternating current of a different number of phases and the same frequency.

A charge of phase whereby an alternating current attains its maximum later or earlier. An inductance would cause a lag, a capacity would cause an advance, in phase.

A device for measuring the difference in phase of two alternating currents of electromotive forces.

The dephasing of the two parts of a single alternating current in two dissimilar branches of a given circuit.

The influence of a coil of wire upon an alternating current passing through it, tending to choke or diminish the current, or the similar influence of a condenser; inductive resistance. Reactance is measured in ohms. The reactance of a circuit is equal to the component of the impressed electro-motive force at right angl…

strument for producing music (Tel*har"mo*ny []), at a distant point or points by means of alternating currents of electricity controlled by an operator who plays on a keyboard. The music is produced by a receiving instrument similar or analogous to the telephone, but not held to the ear. The pitch corresponds with freq…

and an ampere. For direct current it is a measure of power and is the same as a watt; for alternating current it is a measure of apparent power.

Without any power (cf. Watt); -- said of an alternating current or component of current when it differs in phase by ninety degrees from the electromotive force which produces it, or of an electromotive force or component thereof when the current it produces differs from it in phase by 90 degrees.