Explanation: Capacitive transducers are used for the measurement of pressure by converting the pressure into a displacement. The displacement is sensed by a capacitive transducer using a differential arrangement. A thin stainless steel diaphragm which act as the moveable plate is clamped between the discs which is the stationary plates With equal pressures applied (i.e., P1=P2) the diaphragm is in neutral position and the bridge is balanced. The output voltage e0, is zero under the conditions. If one pressure is made greater than the other, the diaphragm deflects in proportion to the differential pressure, giving an output voltage, e0 from the bridge terminal. This output voltage is proportional to the differential pressure. For an opposite pressure difference, the output voltage shows a 1800 phase shift. This voltage may be amplified by an emitter follower amplifier.
Explanation: A diaphragm pressure transducer is used for low pressure measurement. They are commercially available in two types – metallic and non-metallic. The diagram of a diaphragm pressure gauge is shown above. When a force acts against a thin stretched diaphragm, it causes a deflection of the diaphragm with its centre deflecting the most. Its motion is transmitted through the diaphragm, sealed link and pointer drive to the pointer. Then pointer moves over calibrated scale of pressure