An Automated-Switching Precision Decade Capacitor

Abstract

A new automated-switching precision decade capacitor for applications in industries was designed and tested. By using coaxial microwave switches, the automated-switching precision decade capacitor can be automatically set by electrical TTL signals controlled by a computer. To prevent capacitance from drifting caused by variations of ambient temperature, the internal temperature of the automated-switching precision decade capacitor was effectively kept constant using a temperature-controlled oven with sufficiently thermal isolation. Furthermore, to fulfil the compact-size requirement for using at a high frequency, SMD capacitors with NP0 dielectric were used. The temperature stabilities and linearity of the automated-switching precision decade capacitor are presented in this paper.