Measurement Methods for Capacitances in the Range of 1 pF–1 nF: A review

• Overview of capacitance measurement circuits including recent developments. • Comparison of measurement circuits for lossy 1 pF to 1 nF capacitance in terms of measurement time, and accuracy. • Consideration of the influence of conductance loss and stray capacitance on measurement techniques. The rising use of capacitive sensors imposes the need of numerous measuring circuits with different characteristics. Stray fields and conductance losses are thereby key influencing factors that must be taken into account. In this paper, we provide an actual overview of capacitance measurement circuits considering well-known and modern measurement methods, such as lock-in amplifier, relaxation methods, and Martin-based oscillators as well as completely novel classes of capacitance measurement circuits converting the capacitance value directly to digital signals via sigma-delta and dual-slope converter circuit architectures. We classify the capacitance measurement circuits into six categories and address their properties and implementation aspects and compare their performance in a wide the capacitance range. The comparison shows that immunity to stray capacitances and conductive losses is not always given. Capacitance-to-Voltage, Auto-Balancing Bridge, and Capacitance-to-Digital show the best performance in this aspect and are therefore relevant for use in dielectric spectroscopy.