Training Stuff

Introduction about Semi-conductor Strain Gages

release date:2017-02-07 23:53:21


I.Introduction:
SB series semi-conductor strain gage based on piezoresistive effect is made from p-type doped silion wafer,It is ideal component for linear compensation of transducers with column or similar structure. with characters of high sensitivity coefficient, low mechanical hysteresis, broad resistance range and small transverse effect, etc.

II. Linear compensation principle
Due to the unbalance of transverse(Poisson Strain) and axial strain of the column for similar structure transducers element, caused the non-linearity error of the bridge output. and because of the non-linearity between load and strain, material non-linearity, transverse load non-linearity error, severely affect the accuracy of column and similar structure transducers, there we must correct it to meet the requirement of producing high precision transducers.
Non-linear compensation could practice compensation through changing the actual supply voltage of the bridge to compensate transducer linear accuracy.
Generally,in the strain area of the column spring element, on the side of strain gage we just bond two pieces of semi-conductor gages symmetrically along with the axle. as for linear compensation resistance PL.picture 5 shows the bonding area of compensation resistance;connect two pieces of resistance with value of RL/2 symmetrically to the supply bridge.Picture 6 shows the linear compensation bridge and complete bridge circuit.
As we all know, non-linear error of column and similar structure is a degressive parabola. Namely, as the increase of load, output will present degressive trend.After linear compensation, degressive output and increased supply voltage will compensate to each other. therefore the real output will be a straight line.


ModelBacking 
Dim.(mm)
Grid Dim.(mm)Resistance(Ω)
Gage FactorTCR(/℃)TC of Gage 
Factor(/℃)
Max Operating Temp.(℃)Operating Current
(mA)
Strain Limit
(με)
SB5-15-P-26x45x0.32x0.051580±5%<0.06%<0.10%<80206000
SB5-25-P-26x45x0.32x0.051580±5%<0.06%<0.10%<80206000
SB5-30-P-26x45x0.32x0.053080±5%<0.06%<0.10%<80206000
SB5-60-P-26x45x0.32x0.0560100±5%<0.08%<0.12%<80156000
SB5-120-P-26x45x0.32x0.05120110±5%<0.15%<0.15%<80156000
SB3.8-15-P-25x33.8x0.24x0.051580±5%<0.06%<0.10%<80206000
SB3.8-30-P-25x33.8x0.24x0.053080±5%<0.06%<0.10%<80206000
SB3.8-60-P-25x33.8x0.24x0.0560100±5%<0.08%<0.12%<80156000
SB3.8-120-P-25x33.8x0.24x0.05120110±5%<0.15%<0.15%<80156000