Question
What is a choke coil? What is it used for? Explain.
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Answer
A choke coil is an inductor of high inductance. It consists of a large number of turns of thick insulated copper wire wound closely over a soft iron laminated cure- Average power consumed by it over one cycle is $P_{a v}=r_{r m s} i_{r m s} \cos \Phi$, where the power factor $\cos \Phi=$ $\frac{R}{\sqrt{R^2+\omega^2 L^2}}$
For $\omega L>>R, \cos \Phi$ is very low implying power consumption is reduced. The energy loss due to hysteresis in iron core is reduced by using a soft lron core.
In an AC circuit a choke coil is used instead of a resistor to reduce power consumption In case of a pure resistor $P_{a v}$ is high as it is $e_{r m s} i_{r m s}$.
For $\omega L>>R, \cos \Phi$ is very low implying power consumption is reduced. The energy loss due to hysteresis in iron core is reduced by using a soft lron core.
In an AC circuit a choke coil is used instead of a resistor to reduce power consumption In case of a pure resistor $P_{a v}$ is high as it is $e_{r m s} i_{r m s}$.
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