The input quantity causes the change of the capacitance which is directly measured by the capacitive transducer. This overlapping length is changed according to the displacement that is to be measured. The capacitors measure both the static and dynamic changes. Capacitive pressure sensors measure pressure by detecting changes in electrical capacitance caused by the movement of a diaphragm. In general, the process of transduction involves the conversion of one form of energy into another form. The capacitive transducer uses for measurement of both the linear and angular displacement. Advantages: Accurate frequency response Require small forces and power to operate Extremely sensitive device Useful in applications where … So, the distance between these two metal plates and positions of the plates can change the capacitance. Pin Diagram and Description of 8085 Microprocessor, Propagation Characteristics of Radio Waves, By the change in the area of overlapping of the two plates i.e., A, By the change in the distance, d between the two plates. 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.. The sensitivity of the displacement is constant, and therefore it gives the linear relation between the capacitance and displacement. They are also able to measure the thickness or density of non-conductive materials. Capacitive transducer work on the principle of change of capacitance. The figure below shows the parallel plate capacitor, whose 2 plates have width b and are overlapped up to a length l as shown below: It operates in such a way that capacitance of the capacitor is proportional to the area of overlapping of the two plates. Where, C – capacitance 3 Capacitive sensors are realized by varying any of the three parameters of a capacitor: distance between the plates (d), area of capacitive plates (A), and dielectric constant (ε r); therefore Sensors are basically a device which can sense or identify and react to certain types of electrical or some optical signals. So, with the motion of the movable plate, the capacitance increases or decreases depending on the displacement which is to be measured. This can be done by making one or both of the pl… This is the basic working principle of a capacitive transducer. Due to high output impedance, a complicated measuring circuit at the output is needed. The capacitance of the capacitive transducer changes because of many reasons like overlapping of plates, change in distance between the plates and dielectric constant. Hence, by varying either area, distance or permittivity, the non-electrical quantities can be determined. Since capacitance level sensors are electronic devices, phase modulation and the use of higher frequencies makes the sensor suitable for applications in which dielectric constants are similar. A capacitive sensor acts like a simple capacitor. The amount of capacitance varies depending on the size and distance of the sensing object. The phasor diagram of the capacitor is shown in the figure below. It requires small output power for operation. The humidity in gases is measured through the capacitive transducer. The best example of this transducer is a thermocouple. The capacitance at angle θ is given expressed as, θ – angular displacement in radian. x denotes the displacement of dielectric material; l denotes the overlapped region of the two plates. And the dielectric value will determine if you should use a partly or fully insulated probe. how? Since even non-conductors can hold charges, this means that just about any object can be detected with this type of sensor. 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