Question
45.
A series RLC circuit has a resistance of 25 ft, a substance of 0.80 mu F. and an inductance of 250 mH. The Circuit is connected to a variable frequency scarce with a fixed runs voltage output of 12 V. If the frequency that is supplied is set at the circuit's resonance frequency what is the rms voltage across each of the circuit elements? In Exercises 42 and 43 determine the numerical (scalar) stam of the rms voltages across the three circuit elements and explain why it is much larger than the source voltage. Determine the sum of these voltages using the proper phasor techniques and show that your result is equal to the source voltage. If the circuit in Fig 21.17 is in resource, the impedance of the circuit is (1) greater then 25 ft. (2) equal to 25 ft. (3) less than 25 ft. Why? If the driving frequency is 60 Hz, what is the circuit's impedance? A series RLC circuit with a resistance of 400 Ohm has capacitive and inductive reactances of 300 Ohm and 500 Ohm, respectively What is the power factor of the circuit? If the circuit operates 60 Hz, what additional capacitance should be connected to the original capacitance to give a power factor of unity, and how should the capacitors be connected? A series RLC circuit has components with R = 50 ft. L = 0.15 H, and C = 20 mu F. The circuit is driven by a 120-V, 60-Hz and C = 20 mu F, The circuit is driven by a 120-V, 60-Hz source What is the current in the circuit expressed as percentage of the maximum possible current What is the power delivered to the ciruit expressed as a percentage of the power delivered when the circuit is in resonance?
Explanation / Answer
(a) At resonance, XL = XC, so Z = R = 25
Option (2) is correct. Equal to 25 .
b) C = C1 + C2 = 2.5 + 2.5 = 5*10^-6 F
w = 2*pi*60 = 377
XL = wL = 377*0.450 = 169.65
XC = 1/wC = 1/(377*5*10^-6) = 530.5
XT = XC - XL = 360.85 ohm
Z = sqrt[R^2 + XT^2] = sqrt[25^2 + 360.85^2] = 361.7 ohm
