# RLC Circuit

Discussion in 'Homework Help' started by Lexi, Jan 4, 2009.

1. ### Lexi Thread Starter New Member

Jan 4, 2009
6
0
If a series RLC circuit contains a 25 ohm resistance, a 45 ohm capacitive reactance and a 60 ohm inductive reactance, what is the total impedance?

Apr 20, 2004
15,815
283
3. ### jw223 New Member

Jan 3, 2009
9
0
Hi Lexi

When XL > Xc Z = SQRT((R*R) + [(XL - Xc)*(XL*Xc)])

your value; R = 25ohms, XL = 60ohms, Xc = 45ohms

z = SQRT((25*25) + [(60-45)*(60-45)])

Z = 29.155ohms

4. ### jw223 New Member

Jan 3, 2009
9
0

when XL > Xc then z = sqrt((R*R) + [(XL-Xc)*(XL-Xc)])
z = sqrt((25*25) + [(60-45)*(60-45)])
z = 29.155ohms

5. ### mik3 Senior Member

Feb 4, 2008
4,846
63
Impedance of the capacitor is -j45 ohm, of the inductor is +j60 ohm and of the resistor is 25 ohm.

Thus,

total impedance Z=25+j60-j45=25+j15

in polar form

|Z|=sqrt[(25^2)+(15^2)]=29.15

arg Z=arctan (15/25)=30.9 degrees

thus Z=(29.15<30.9) ohm

6. ### mik3 Senior Member

Feb 4, 2008
4,846
63
This is always true, not only when XL>Xc.