Variable Capacitance Pressure Sensor

The capacitive transducer is used for measuring the displacement pressure and other physical quantities.

Variable capacitance pressure sensor. Automotive systems laboratory inc. Typically one electrode is a pressure sensitive diaphragm and the other is fixed. A pressure sensor usually acts as a transducer. Output current of 4 to 20 ma.

Capacitive pressure sensors with high linearity by optimizing electrode boundaries us6056079a en 1996 12 19. This imbalance is detected in a capacitance bridge circuit and converted to a d c. Stress relieving means are provided to eliminate hysteresis effects from the connecting structure. The capacitive pressure sensor operates on the principle that if the sensing diaphragm between two capacitor plates is deformed by a differential pressure an imbalance of capacitance will occur between itself and the two plates.

It generates a signal as a function of the pressure imposed. For the purposes of this article such a signal is electrical. The capacitance of the capacitive transducer changes because of many reasons like overlapping of. The conducting surfaces forming the capacitor are insulated from the central connection and each other.

The capacitive transducer comprises of two parallel metal plates that are separated by the material such as air which is called as the dielectric material. In the typical capacitor the distance between the two plates is fixed but in variable capacitance transducers the distance between the two plates. An easy way of measuring the change in capacitance is to make it part of a tuned circuit typically consisting of the capacitive sensor plus an inductor. The capacitive transducer or sensor is nothing but the capacitor with variable capacitance.

The advantages of this technology are obvious in measurement sensitivity at low pressure ranges. Endress hauser gmbh co. The capacitive transducer works on the principle of variable capacitances. A pressure sensor is a device for pressure measurement of gases or liquids pressure is an expression of the force required to stop a fluid from expanding and is usually stated in terms of force per unit area.

Typical variable capacitance sensor cross section. The structure provides decreased thermal path lengths to reduce thermal effects. The capacitance pressure transmitter is a pressure measurement device. Viatran differential pressure transmitters make use of variable capacitance technology as do the viatran gage type and absolute pressure sensors.

This is shown in figure where the movement of a. It is a passive transducer that means it requires external power for operation. Capacitive pressure sensor having a substrate with a curved mesa us5792957a en 1993 07 24. What is the capacitive pressure transducer.

A variable capacitance sensor is constructed with its capacitance plates connected at their center.