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LESSON NOTES:

AC Current
which current direction changes after equal intervals of time, then the current is called
an alternating current (abbreviated as AC).

Direct Current
When the current flows in the same direction and does not change direction, it is called
Direct current (DC)

Facts about AC and DC currents
(a) Most power stations constructed these days produce AC.
(b) In India, the AC changes direction after every 1/100 second, that is, the frequency of
AC is 50 Hz.

Advantages of alternating current (AC) over direct current (DC) :

 AC is easy and cheaper to generate than DC.

 AC can be transferred to long distance as compared to DC.

 Power loss in AC is less as compared to DC during transmission.

 AC can be easily converted into DC.

 AC can be generated at high voltages, but DC cannot be generated at high
voltages because sparking starts at the commutator at high voltage, due to which
commutator gets damaged.

 Alternating current can be stepped up or stepped down with a static device called
transformer.

Disadvantages of ac over dc