- Alternating current is defined as the current that varies like a sine function with time.
- The value of current will oscillate between a maximum value and a minimum value.
- In case of AC the current is changing its magnitude at every instant of time.
- The direction of current will be clockwise and anticlockwise and it will keep on repeating.
- Frequency of the alternating current is defined as how fast the electrons are changing their directions. For example: If frequency is 20Hz this means electrons are moving back and forth 20 times in a second.
- DC voltage gives rise to DC current similarly AC voltage give rise to AC current.
- Alternating current is expressed as: - I = Im sinωt
- Where Im = maximum or peak value of the AC .
- Alternating voltage is expressed as: - V = Vm sinωt
- Where Vm = peak value of the voltage.
Causes of alternating current
- When a rotating magnet is considered instead of steady magnetic field then both the poles of the magnet will keep on changing as a result the direction of electrons also gets reversed.
This results oscillation of electrons which give rise to current and this current is known as alternating current.
(AC as a sine wave function)