If Vm and Im are peak voltage and current, Impedance Z in an AC circuit is
Impedance refers to the overall obstruction offered by a circuit containing different components to the passage of current. Also Z has unit same as resistance.
So, drawing an analogy with the ohm's law, we get the above relation
Impedance in series LCR circuit
at resonance
in LCR series circuit current
at resonance
hence current will be maximum.
Sharpness of resonance is quantitatively described by a dimensionless number known as Q-factor or quality factor which is numerically equal to ratio of resonant frequency to bandwidth.
therefore
Q-factor = resonant frequency / bandwidth
sharpness of resonance =
in parallel LC circuit, Impedance
at resonance
hence impedance will be infinite.
inductive reactance
rms current
Peak value of voltage
rms value of current