Capacitance in RLC circuit

Thread Starter

Biggsy100

Joined Apr 7, 2014
88
I am having trouble working out how to equate capacitance in an RLC series circuit. I have a small paper with both series and parallel RLC circuit question (attached) I believe my equations are correct up until the last capacitance question then I am stuck. I'd greatly appreciate confirmation I am on the right track and guidance in working out capacitance.

Task 1 Parallel RLC Circuit:

A coil of resistance 20Ω and inductance 200mH is connected in Parallel with a 4µF capacitor across a 50V, Variable frequency supply, Calculate

  1. The resonant Frequency


    upload_2015-5-23_17-15-31.png= upload_2015-5-23_17-15-31.png


  2. Dynamic Resistance


    upload_2015-5-23_17-15-31.png= upload_2015-5-23_17-15-31.png
(c )The current at resonance

upload_2015-5-23_17-15-31.png= 2.5A

(d ) & The Q-Factor of the circuit at resonance

upload_2015-5-23_17-15-31.png=upload_2015-5-23_17-15-31.png


Task 2 Series RLC circuit:

The current at resonance in a series LCR circuit is 135µA. If the applied voltage is 3.5Mv at a frequency of 200kHz, and the circuit inductance is 47µF, Calculate:

(a ) The circuit resistance:

upload_2015-5-23_17-15-31.png= upload_2015-5-23_17-15-31.png 20.357

(b ) The circuit capacitance:

upload_2015-5-23_17-15-31.png= upload_2015-5-23_17-15-31.png= ???











 
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