Practical and simple circuitry for the measurement of small capacitance

D. Y. Lin, J. D. Wu, Y. J. Chang, J. S. Wu

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Practical and cost-effective circuitry with high sensitivity has been developed to measure a small capacitance using current compensation method. The circuitry uses an electronic switch to periodically connect or separate the capacitor under test (Cx) from a reference capacitor (Cr). When Cx is connected in parallel with Cr the total capacitance becomes Cx + Cr. On the other hand, as Cx is separated from Cr, the total capacitance is only Cr. This periodic change of the capacitance generates a periodic square-wave output with an amplitude in proportion to the capacitance of Cx. A high sensitivity of ΔVΔC= 202.2 mVpF has been achieved, making the circuitry a powerful tool in measuring small capacitances. Three applications have been performed to present its capability: (a) displacement, (b) height of liquid, and (c) angle of tilt. The experimental results demonstrate the performance of the circuitry.

Original languageEnglish
Article number014703
JournalReview of Scientific Instruments
Issue number1
Publication statusPublished - 2007 Apr 8

All Science Journal Classification (ASJC) codes

  • Instrumentation

Fingerprint Dive into the research topics of 'Practical and simple circuitry for the measurement of small capacitance'. Together they form a unique fingerprint.

Cite this