Re: Basic question about commom source amplifier with inductor
Without knowing for what application the above circuit is intended to be used, it is somewhat difficult to evaluate, but your analysis is correct. For a resonance frequency of the LC tank, the gain would be maximum since the impedance of the resulted reactance of the conjugates XL and XC tends to infinite (resulted admitance of subtraction of both tend to zero), limited by the quality factor of the filter, in other words, of the losses in those components. Note that the value of RD that is needed to bias the transistor M1 in a linear region is a limiting factor for the maximum gain before the RC network start to attenuate the gain. Anyway, all this seems to be rather a circuit analysis within the theoretical scope than a comparison of actual circuits for the same application in real world.