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The rms voltage of the generator is V_0 The frequency of the ac generator is verynear zero. What is the rms current through the circuit? |
Answer» Solution :As we just now discussed, at small frequencies, the circuit is like a dc circuit. So, the capacitor can be replaced by a open circuit and inductor by a short circuit. Figure 31-22 shows the circuits as they would appear according to these CHANGES.  It is obvious from the circuit that it is not a circuit of series elements , nor elements in parallel.  Calculation : The rms current is given by `I_(rms)=V_(rms)/Z`. However, the impedance Z . because the circuit is not series RCL circuit. The circuit behaves as if it contained only two identical resistors in series, with a total impedance of Z=2R. Thus circuit has `I_(rms)=V_(rms)/(2R)`. Learn: If the source had a very HIGH frequency (much HIGHER than the RESONANCE frequency), the capacitor would be treated as short-circuited and inductor as open-circuited. Figure 31-23 shows the circuits as they would appear according to these changes. So, at this frequency, the impedance of the circuit would be R/2. Hence `I_(rms)=(2V_(rms))/R`. 
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