Pressure measurement with strain gauges on diaphragm:
Description: This method uses the principle of converting pressure into a displacement by elastic elements which act as primary transducers. The displacement created is converted into an electrical parameter by secondary transducers. The figure above shows an arrangement of pressure measurement using four strain gauges mounted on a flat diaphragm. The gauges are electrically connected in a bridge circuit as shown in the figure. The diaphragm act as primary transducer and bonded strain gauges as secondary transducers. As pressure is applied, the diaphragm deflects causing radial and tangential stresses on the strain gauges. The stress cause strain on the gauges, changing the resistance of strain gauges. The change in resistances produce unbalance in the bridge circuit, producing an output voltage proportional to the applied pressure.