The Phase Constant
From the right-hand phasor triangle in  Fig. 3114d and from  Table 31-2 we can write
The other half goal  an equation  for the
phase constant 
 in a sinusoidally driven 
series RLC circuit.
Phase constant   gives different results 
depending on the relative values of 
XL  Xc
207
XL > Xc
XC > XL
208
XC = XL
209
Resonance
Equation 31-63 
I maximum  when  dL – 1/dC = 0
Natural angular frequency   of the RLC circuit
 equal to  1/LC
Resonance and Maximum  current amplitude I
occur when
210
211
In summary
The low-angular-frequency side
of a resonance curve  dominated by the capacitor's
reactance,
The high-angular- frequency side
is dominated  by the inductor's reactance, and
resonance occurs in
the middle.
Ans: a) 1 lags : 2 lead: 3 in phase. b) 3 (d =  when XL
= XC
212
213
214