Strain gauge transducer types and workingStrain gauge is a type of transducer which is used to measure Strain ( Linear or angular force) force.
1. Change in length
2. Change in diameter
3. Change in resistivity
By using a electric circuit we measure the changes of resistance and by use this also measure applied force
According figer when applied tensile force on metal his diameter varies from "D" to "d " and their length also varies "L" to "l" so resistance are also varies from "R" to "r"
so gauge factor
GF = r/R divide by l/L
GF = 1 to 2
Type of strain gauge transducer1. Unbounded type strain gauge
2. Bonded type strain gauge
3.Bonded metal foil strain gauge
4. Semiconductor Strain gauge
1. Wheatstone bridge strain gauge transducerUnbound type strain gauge made from different material
Wheatstone bridge condition
P/Q = R/S
where p q r s is resistance
Voltage E = 0 ( in balance condition)
when force applied on diaphragm unbalance create and resistance change so out put terminal get o/p volatile . which is strain force, ( this voltage is directly proportional to applied force ) . so voltmeter shows reading of applied force
2. Bonded type strain gaugeIn bonded type strain gauge we use paper , bake light , teflon on grid element . it use like a base to protect from wire and also provide mechanical protection.
3. Bonded metal foil strain gaugeIt is also type of Bonded type strain gauge but in this type strain gauge polymide or glass used as a grid base.
4. Semiconductor strain gaugeIn semiconductor strain gauge silicon , germanium and other material used when applied force more resistivity changes become which used more force me can measure.
Advantage of semiconductor strain gauge
1. higher gauge factor
2. high sensitivity
3. Long life
4. Small size
5. Low cost
6. higher heat dissipation capacity