Baxter L.K. Capacitive Sensors: Design and Applications

IEEE Press, 1997, 302 pages, ISBN 0-7803-1130-2Capacitive sensors can solve many different types of sensing and measurement problems.They can be integrated into a printed circuit board or a microchipand offer noncontact sensing with nearly infinite resolution.They are used for rotary and linear position encoding, liquid level sensing, touch sensing, sensitive micrometers, digital carpenter's levels, keyswitches, light switches and proximity detection. Your telephone and tape recorder probably use electret microphones with capacitive sensing, and your car's airbag may be deployed by a silicon accelerometer which uses capacitive sensing. The use of capacitive sensors is increasing rapidly as designers discover their virtues.The book is organized as follows.
Basics This section covers theoretical background, different electrode geometries, and basic circuit designs.
Applications Four different uses of capacitive sensors are presented: micrometers, proximity detectors, motion encoders, and some miscellaneous sensors. The theory behind these different uses is discussed.
Design The electrode configurations and the basic circuit designs which were briefly discussed in the Basics section are more fully explored here.
Products This section presentsdesign details of several different products which use capacitive sensors.