What is "electric current"

Electricity \E`lec*tric"i*ty\ ([=e]`l[e^]k*tr[i^]s"[i^]*t[y^]), n.; pl. Electricities ([=e]`l[e^]k*tr[i^]s"[i^]*t[i^]z).

1. (Physics) a property of certain of the fundamental particles of which matter is composed, called also electric charge, and being of two types, designated positive and negative; the property of electric charge on a particle or physical body creates a force field which affects other particles or bodies possessing electric charge; positive charges create a repulsive force between them, and negative charges also create a repulsive force. A positively charged body and a negatively charged body will create an attractive force between them. The unit of electrical charge is the coulomb, and the intensity of the force field at any point is measured in volts.

2. any of several phenomena associated with the accumulation or movement of electrically charged particles within material bodies, classified as static electricity and electric current. Static electricity is often observed in everyday life, when it causes certain materials to cling together; when sufficient static charge is accumulated, an electric current may pass through the air between two charged bodies, and is observed as a visible spark; when the spark passes from a human body to another object it may be felt as a mild to strong painful sensation. Electricity in the form of electric current is put to many practical uses in electrical and electronic devices. Lightning is also known to be a form of electric current passing between clouds and the ground, or between two clouds. Electric currents may produce heat, light, concussion, and often chemical changes when passed between objects or through any imperfectly conducting substance or space. Accumulation of electrical charge or generation of a voltage differnce between two parts of a complex object may be caused by any of a variety of disturbances of molecular equilibrium, whether from a chemical, physical, or mechanical, cause. Electric current in metals and most other solid coductors is carried by the movement of electrons from one part of the metal to another. In ionic solutions and in semiconductors, other types of movement of charged particles may be responsible for the observed electrical current. Note: Electricity is manifested under following different forms:

   1. Statical electricity, called also

      Frictional electricity or Common electricity, electricity in the condition of a stationary charge, in which the disturbance is produced by friction, as of glass, amber, etc., or by induction.

   2. Dynamical electricity, called also

      Voltaic electricity, electricity in motion, or as a current produced by chemical decomposition, as by means of a voltaic battery, or by mechanical action, as by dynamo-electric machines.

   3. Thermoelectricity, in which the disturbing cause is heat (attended possibly with some chemical action). It is developed by uniting two pieces of unlike metals in a bar, and then heating the bar unequally.

   4. Atmospheric electricity, any condition of electrical disturbance in the atmosphere or clouds, due to some or all of the above mentioned causes.

   5. Magnetic electricity, electricity developed by the action of magnets.

   6. Positive electricity, the electricity that appears at the positive pole or anode of a battery, or that is produced by friction of glass; -- called also vitreous electricity.

   7. Negative electricity, the electricity that appears at the negative pole or cathode, or is produced by the friction of resinous substance; -- called also resinous electricity.

   8. Organic electricity, that which is developed in organic structures, either animal or vegetable, the phrase animal electricity being much more common.

3. The science which studies the phenomena and laws of electricity; electrical science.

4. Fig.: excitement, anticipation, or emotional tension, usually caused by the occurrence or expectation of something unusual or important.

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).

alt. 1 (context physics English) A movement of electrons. 2 A flow of electricity through a conductor. n. 1 (context physics English) A movement of electrons. 2 A flow of electricity through a conductor.

n. a flow of electricity through a conductor; "the current was measured in amperes" [syn: current]

The SI unit for measuring an electric current is the ampere, which is the flow of electric charge across a surface at the rate of one coulomb per second. Electric current is measured using a device called an ammeter.

Electric currents cause Joule heating, which creates light in incandescent light bulbs. They also create magnetic fields, which are used in motors, inductors and generators.

The particles that carry the charge in an electric current are called charge carriers. In metals, one or more electrons from each atom are loosely bound to the atom, and can move freely about within the metal. These conduction electrons are the charge carriers in metal conductors.