Using a variable frequency a.c. voltage source the maximum current measured in the given LCR circuit is 50 mA for V = 5 (100t). The values of L and R are shown in the figure. The capacitance of the capacitor (C) used is . [figure]
Answer
50
Solution
Peak current I0 = V0Z; with V0 = 5 V and R = 100 :
I0 = 50 mA = 5100 A = V0R Z = R, i.e. the circuit is at resonance at = 100 rad/s
At resonance = 1 LC
C = 1 2 L = 1(100)2 2 = 5 10-5 F
C = 50
Answer: 50