Transcript bridge voltage divider

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“Precision Uncertainty”
or “resolution uncertainty” – URES = half of the smallest division
Distance x
cm
L = 9.4 ± 0.5 cm
Significant digits or “sig figs”
L = 9.4 ± 0.5 cm
correct!
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L = 9.4204 ± 0.5 cm
incorrect!
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Uncertainty and Error
error – The difference between what you measured and the
actual value
uncertainty – an estimate of the error
-Instrument uncertainty – due to shortcomings of the instruments
-Repeatability uncertainty – due to statistical variation in the
measured values
“human error” – means you made a mistake doing the
experiments—do not use this phrase unless you made a
mistake!
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Strain Gauge (or Gage)
Measures strain based
on change in resistance
rL
R=
A
Ge ≈ 2
“gage factor”
Fig. 4.4
Often wired up in a
Wheatsone bridge
configurartion
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RTD – Resistance Temperature Detector
The resistivity of a metal changes
linearly with temperature.
éR - R ù
0
T = T0 + ê
ú
ë a T R0 û
Lab1: Voltage divider circuit
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Thermistor
sors/Transducers
Works the same as an RTD, except the sensing
material is made
of a ceramic or a semiconductor.
ce (RTD)
Thermistor
asurement
resistance-based temperature measurement
Lab 1
10000 ! resistor
in voltage divider
circuit
Aerospace and Mechanical Engineering
aboratory
é æ 1 1 öù
R = R0 expê bT ç - ÷ú
ë è T T 0 øû
Spring 2016
Appendix B
300 ! )
ground,
Steinhart Eq.
Model: Vishay BCcomponents 2381!640-64103
Transducer: voltage divider (R = 10000 ! )
Wires: red – power (5 V), black – ground, blue
– output voltage
Response: semi-log
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Non-linear response
é
ù
T0
ú
T =ê T
êë ( 0 b T ) ln( R R0) +1 úû
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