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Always remember that mean value of AC over a complete cycle is zero and is defined over a half cycle of AC .
Root
Mean square value of AC
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Instantaneous current I and time average of AC over half cycle could be positive for one half cycle and negative for another half cycle but quantity i 2 would always remain positive So time average of quantity i 2 is
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This is known as the mean square current The square root of mean square current is called root mean square current or rms current . Thus ,
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