Alternating Circuit

What is an alternating current?

Electric current is nothing but the movement of electric charges. The movement of electrical charges is not always in uniform direction, if it is travelling in single direction, then it is considered as direct current, but when the charges travelling in alternate direction (to and fro), then it is considered as alternating current. Circuit which carries alternating current is called alternating circuit.

AC versus DC:

The study of electricity always begins with direct current, because it is very simple and easy to understand its nature, but it has lot more disadvantages when compared with AC.

Advantages of AC which is not in DC:

In generators:

Generators are electricity producers working under the principle of electromagnetic induction. Generators built to produce AC & DC are totally different. AC generators have magnet as a rotating shaft situated between the electric coils. This magnet will rotate without any contact to electric coils, but in DC generators, the rotating material is an electric coil situated between magnets and the rotating coil will have contact with transmitting coils with the help of carbon brushes. While generators revolving at higher speed, the electric sparks or heat may be produced and resulted in danger when any inflammable materials are placed near to the generator.

In motors:

Structure of the AC and DC motors are almost same as AC and DC generators as well as the dangers are also the same we met in generators.

In transmission:

It is more conventional that AC is used to transmit current for a long distance instead of DC, because power loss is more when DC is supplied and high voltage should be needed to supply DC and more expensive for lengthier wires. These problem are rectified when we transmit current using AC

In transformers:

The current has been supplied from power stations to consumers for a long distance with high voltages, but equipments or appliances will work in less voltage. To increase or decrease voltage wherever it is required, transformer is placed.

The principle of transformer is suitable for AC only not to DC, because DC produce steady current which is not suitable to transformers.