Measurement of the Gain Bandwidth-Product of the Op-amp:
The equivalence of Figure (b) recommend an interesting way of measuring the gain bandwidth product of an op-amp. By connecting an inductor L in series with this circuit a series resonant circuit is acquired for which the resonant frequency given by
f0 = 1/ [2π (L / A0 ωp Rp )](1/2)
may be easily determined experimentally. A0 ωp may then be determined because R, L and f0 are known.