Subject: Physics
When a battery is connected to a circuit, the current flows steadily in one direction. It is called a direct current. Electric generators at electric power plants, however, produce alternating current due to many technical reasons. Alternating current results when a sinusoidal e.m.f or voltage is applied in a circuit. Circuits fed by the alternating source are known as A.C. circuits. Alternating current (AC) circuits carry energy due to the coordinated vibrations of neighboring electrons. While DC circuits require single electrons to (slowly) move through the circuit and carry energy thanks to the kinetic energy carried by electrons as they drift through the wire, AC manages to carry energy without any overall motion of the electrons through the circuit.
The current or e.m.f., whose magnitude changes with time and direction reverses periodically is known as alternating current or e.m.f.
The instantaneous values of alternating current and e.m.f at any time t are given by
\begin{align*} I &= I_0 \sin \omega t \dots (i) \\ E &= E_0 \sin \omega t \dots (ii) \end{align*}
where I0 and E0 are their maximum value or peak value or amplitude of current and e.m.f respectively. Their angular frequency is called driving frequency and is given by
$$\omega = \frac {2\pi }{T} = 2\pi f $$
Where T is time period and f is frequency of alternating current or e.m.f.
Advantages
Disadvantages
Reference
Manu Kumar Khatry, Manoj Kumar Thapa, Bhesha Raj Adhikari, Arjun Kumar Gautam, Parashu Ram Poudel.Principle of Physics. Kathmandu: Ayam publication PVT LTD, 2010.
S.K. Gautam, J.M. Pradhan. A text Book of Physics. Kathmandu: Surya Publication, 2003.
When a battery is connected to a circuit, the current flows steadily in one direction. It is called a direct current.
Alternating current (AC) circuits carry energy due to the coordinated vibrations of neighboring electrons.
The current or e.m.f., whose magnitude changes with time and direction reverses periodically is known as alternating current or e.m.f.
AC can be better controlled without any loss of electric power by using a choke coil.
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