In electronics what is a current?

Answer 1

An electronic current is what occurs when electrons move in a definitive direction. Not to be confused with voltage (V).

The electrons (sometimes referred to as charges) move from a region of overall negative polarity towards a region of overall positive polarity because they, themselves, are negatively charged.

Opposite polarities attract just like the north and south of a magnet.

Electrons (charges) can only move through a conductor if a potential difference has been created between the two 'poles' of the conductor.

If there is a difference (more electrons at point A in a circuit than at point B) then the conductor is said to be holding a charge.

Any circuit that is storing a charge has the 'potential' to create a current. A current will flow when the electrons are allowed to travel from point A to point B.

Example:

When a battery is connected in series with a lamp the electrons travel from the negative terminal on the battery, along the conductor, through the lamp (causing it to illuminate, and back through the other conductor to the positive terminal of the battery.

The bulb will remain lit until there is an even distribution of electrons in each pole of the battery (assuming that the circuit is not severed).

When the electrons are evenly distributed at each end of the battery then the battery is said to have lost it's charge. When the battery has lost its charge the current will stop flowing.

Current is measured in Amperes (Amps) and has the symbol I. {simple enough}

Charge (Q) is measured in culombs. The symbol C . {a little confusing but true}

The quantity (Q) of charge carried by roughly 6 million, million, million electrons is named 1 culomb and has the cymbol C. {makes above less confusing}

If this many electrons (1 culomb) pass each point in a circuit every second then the current at that point is 1 Ampere.

formula:

1A = 1C/s

Q is a symbol used to describe a number of culombs e.g

if 2C pass in 1 second the current is:

2 C/s = 2A

In general if Q coulombs pass in t seconds, then the current I is given as:

Q = It or I=Q/t.