what will be eqn of AC and AV in LC circuits?

Asked by prakasan | 11th Sep, 2010, 12:00: AM

Expert Answer:

Dear Student

You may treat LC circuit as LCR circuit with R being accounted for as resistance offered by the either the load or the connecting wires.
Following is the discussion which leads to the voltage & current values in the LCR circuit.

The voltage phasor in  the LCR circuit will be given by

Taking the dot product



Vo2  = (VR)2o + (Vc +VL).(Vc +VL)

= (VR)2o +[(VL)o  - (Vc)o]2

= [R2 +(Xc - XL)2]Io2

From this, we immediately get
peak value of the current as   Io=Vo/Z where

The factor Z is the analog of resistance in a purely resistive circuit, and is called Impedance.

The phase is immediately found from the simple phasor picture

If Xc >XL, Φ >0, and the circuit is more Capacitive and if 

 Xc L, Φ <0, the circuit is predominantly Inductive.

Hope this clarifies your query.

Answered by  | 14th Sep, 2010, 10:30: AM

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