公元前

[计] 存取周期, 累加器, 声耦合器, 交流, 应用控制, 自动检查, 自动计算机

[化] 交流; 交变电流

electric current \electric current\, electrical current
\electrical current\,
the movement of electrically charged particles, atoms, or
ions, through solids, liquids, gases, or free space; the term
is usually used of relatively smooth movements of electric
charge through conductors, whether constant or variable.
Sudden movements of charge are usually referred to by other
terms, such as {spark} or {lightning} or {discharge}. In
metallic conductors the electric current is usually due to
movement of electrons through the metal. The current is
measured as the rate of movement of charge per unit time, and
is counted in units of amperes. As a formal definition, the
direction of movement of electric current is considered as
the same as the direction of movement of positive charge, or
in a direction opposite to the movement of negative charge.
Electric current may move constantly in a single direction,
called {direct current} (abbreviated {DC}), or may move
alternately in one direction and then the opposite direction,
called {alternating current} (abbreviated {AC}).
[PJC]


AC \AC\ n. [Acronym from alternating current.]
an electric current that reverses direction sinusoidally.
Alternative to {direct curent}, {DC}. [acron.]

Syn: alternating current
[WordNet 1.5]

Ac \Ac\ n.
1. the chemical symbol for {actinum}, a radioactive element.

Syn: actinium
[WordNet 1.5]