Why is the series resonant circuit called an acceptor circuit?
Because the series resonant circuit has the lowest possible
impedance at resonance frequency, thus allowing the AC current to
circulate through it. At resonance frequency, XC=XL and XL-XC = 0.
Therefore, the only electrical characteristic left in the circuit
to oppose current is the internal resistance of the two components.
Hence, at resonance frequency, Z = R. Note: This effect is probably
better seen with vectors. Clarification: Resonant circuits come in
two flavors, series and parallel. Series resonant circuits do have
an impedance equal to zero at the resonant frequency. This
characteristic makes series resonant circuits especially well
suited to be used as basic pass-band filters (acceptors). However,
parallel circuits present their maximum impedance at the resonant
frequency, which makes them ideal for tuning purposes.