Abstract
An automatic C-V plotter which employs phase-locked loop integrated circuits to sense the in-phase and quadrature-phase current signal passing through the diode under test is described. The output voltage at a moderately high frequency is directly proportional to the junction capacitance of the diode when the reference signal of the phase detector is in phase with the input signal. The junction resistance of the diode can be simultaneously determined by measuring the quadrature-phase signal. This instrument has successfully measured the C-V characteristics of Schottky barrier solar cells.