A portable nodal impedance analyser. The impedance analyser (100) is configured with an auto best curve-fit application which automatically selects the values for Voltage, Source Impedance and Frequency of the stimulus waveform (best fit values) to generate equivalent circuit and its appropriate V-I traces. The auto best curve-fit application automatically selects one or more input Sinusoidal Patterns (Waveforms) in such a way that the V-I Characteristics of the components present in a Node (the two points across which the input Pattern is driven, and response is received), are best revealed by automatically adjusting the Drive Voltage (0.2V, 4V, 8V and 13V), Source Impedance (10Ω, 50Ω, 100Ω, 500Ω, 1KΩ, 5KΩ, 10KΩ, 50KΩ, 100KΩ) and Frequency (from 1 Hz to 50 KHz) of the input Patterns.