# Alternating Current

Card 1: Direct Current

## Direct Current

Direct current is uniform current flowing in one fixed direction in a circuit.

The magnitude of a direct current can be either uniform or varying with time.

Direct current (d.c) is usually supplied by acid-based batteries or dry cells.

Card 2: Alternating Current

## Alternating Current

Alternating current is a current which changes its direction periodically in a circuit.

Alternating current (a.c) is generated from alternating current generators such as hydroelectric power generators. Its magnitude also changes with time.

Card 3: Period and Frequency of an Alternating Current

## Period and Frequency

The time taken for one complete cycle is known as the period, T.

The frequency f is defined as the number of complete cycles in 1 second.

The relationship between the frequency and the period is:

Card 4: Root mean square voltage

## Root Mean Square Voltage

The effective potential difference for an a.c is equal to the potential difference of a alternating current if both results in the same heating effect.

The effective potential difference for a.c is known as the root mean square voltage (r.m.s) of the a.c. and is given y the following equation:

Card 5: Can direct current or alternating current passing through a capacitor?

## Direct Current and Alternating Current with Capacitor

A direct current (d.c.) cannot flows through a capacitor.

An alternating current (a.c.) can flows through a capacitor.

Card 6: Can direct current or alternating current cause an effect to a moving coil loud speaker?

## Direct Current and Alternating Current with Capacitor

A direct current (d.c.) causing no effect on the moving coil loudspeaker.

An alternating current (a.c.) can cause a moving coil loudspeaker functioning properly.

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