Page 171 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

V V V
R X XI
I L I C I
R L C G 2 2
2 2
Y
1 Y G B BB B C C
L L
Z
2 2 1 1 1 1
wher

Y
1 1 1 where :e : Y G G
Z Z R R
R X L X C L L
1 1 B B C
B
C
B

L
1 1 2 1 1 2 L L L C C

Z R X L X C

RLC Parallel circuit-at resonance
Consider an ideal parallel resonant circuit,

it consists of ideal resistance less inductor connected parallel with a perfect insulator. when the frequency of
the applied voltage is such that xl=xc it become parallel resonant circuit. it means that the capacitor discharges
exactly at the instant when the coil needs current to build up its magnetic field .it is so because there is a phase
difference of 1800 between current drawn by the two. current drawn by the supply is zero (ideal case) and circuit
offer maximum impedance to the circuit
at resonance,
XL= XC
Z = R (maximum)
I = minimum

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CITS : Power - Electrician & Wireman - Lesson 26-29