Definition : an electromechanical sensor used to convert mechanical motion or vibrations, specifically rectilinear motion, into a variable electrical current, voltage or electric signals, and the reverse.

the electrical resistance change of a manganin (alloy of Cu, Ni, Mn) or gold chrome wire, with hydrostatic pressure to accommodate a bulk compression effect.

The voltage at point D = V × RX / (R3 + RX)

The voltage at point C = V × R2 / (R1 + R2)

The voltage (V) across galvanometer or between C and D is, VCD = V × RX / (R3 + RX) − V R2 / (R1 + R2)

For finding the unknown value of resistance RX = R3 × (R2 / R1)

Pressure applied to the pressure transducer produces a deflection of the diaphragm which introduces strain to the gages.

Definition : pressure transmitter, is a transducer that converts pressure into an analog electrical signal. One of the most common is the strain-gage base transducer.

the electrical resistance change of a manganin (alloy of Cu, Ni, Mn) or gold chrome wire, with hydrostatic pressure to accommodate a bulk compression effect.

Definition: an elastic-element type of pressure transducer. It is commonly used for measuring the gauge pressure of both gaseous and liquid fluids.

When pressure applied the elastic elements will get deformed. Based on this deformation, the pressure can be measured.

Should have negligible surface tension and capillary effects.

Low viscosity to ensure quick respond to pressure changes.

Non-corrosive and not have any chemical reaction with the fluid which pressure is being measured.

Atmospheric pressure: at sea level is nearly 1.013x10⁵ N/m² or 760 mm of Hg. (Pressure in the surrounding air)

Absolute pressure: fluid pressure above the reference value of a perfect vacuum or the absolute zero pressure.

Gauge pressure: pressure above the reference value of atmospheric pressure.

Pressure is (P = F/A) SI unit : Pascal (Pa) = N/m²

Vacuum measurement unit are Torr and micron.One Toor is a pressure equivalent of 1 mm of Hg while 1 micron is 10¯³ Torr.

An instrument for measuring very low gas pressures (1 μPa to 1 Pa) based upon the momentum transfer by gas molecules between two closely-spaced plates immersed in the gas

The ionization gauge is a special type of instrument used for measuring very low pressures in the range 10^-13 to 10^-3 bar.

Pirani gauge is similar to a thermocouple gauge but has a heated element that consists of four coiled tungsten wires connected in parallel.

Such gauges cover the pressure range 10^- 5 mbar to 1mbar.

Equation for applied pressure using McLeod gauge .The minimum pressure normally measurable is 10^-4 bar Pu = ah^2/Vu