The quantity Z is called impedence, and it represents effective resistance to the current flow. In complex number representation we may write
![](p29.gif)
Then the combinations of impedences is analogou to those of Resistances. As an illustration the series
L-C-R circuit solution can be obtained as follows :
![](p30.gif)
![](p31.gif)
Solved Problems
1. A resistance of 100 ohm is connected to a capacitance of 1
mf in series. Find the time constant of the circuit. If a 2 volt D.C. e.m.f. source is connected to the circuit, after how long the p.d. across capacitor will become 0.66 volt?
Solution
![](p32.gif)
2. Find the condition for resonance of a series L-C-R circuit driven by A.C.e.m.f. source e = e0
sin(wt).
Solution
![](p33.gif)
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Index
26.1 R-C and
L-R D.C Circuits
26.2 Reactance and impedance of L,C,R
Chapter
27
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