Method and apparatus for high speed resistance, inductance and

Abstract

A method of, and an apparatus for, high speed resistance (R), inductance (L) and capacitance (C) measurement is disclosed. A voltage or current based excitation signal having a very low voltage level and a predetermined waveform is applied to the item whose R, L or C parameter(s) is (are) to be measured; and, voltage measurements are made at predetermined points in the time domain of the output voltage waveform. Whether the excitation signal is voltage based or current based, the particular shape of the waveform (preferably trapezoidal or dual polarity rectangular wave) and the voltage measurement points in the time domain of the output voltage waveform are determined by: (i) the nature of the parameter (R, L or C) to be measured; (ii) the magnitude of the parameter (small or large) in the case of R and C parameters; and, (iii) the series/parallel nature of the parameters in situations where significant amounts of two parameters coexist in the item being measured. The measured voltage values are used to determine the value(s) of the R, L or C parameter(s). The voltage level of the excitation signal can be maintained below the activation level of contemporary printed circuit board active circuit elements (e.g., transistors), without loss of accuracy. As a result, the invention can be used to measure the R, L and C parameters of in-circuit components.