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15 Cards in this Set
- Front
- Back
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Thermistor |
A type of resistor whose resistance is dependent on temperature, more than standard resistors -small -large sensitivity -long term stability -operates at a small amount of power |
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Radiation thermometry |
Uses the relationship between the surfaces temperature of an object and it's radiant power to find a measurement of the temperature of a body with no physical contact |
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Measurand |
The physical quantity, property, or condition that the instrumentation system measures |
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Sensors |
Convert a physical measurand to an electric output -strain gage: convert displacement to an electric voltage -force sensor: Changes force to electrical voltage |
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Example of direct |
ECG Temperature |
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Example of indirect |
Cardiac output X-ray |
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Precision |
Hitting the same place each time |
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Displacement measurement principles |
Reveals information about size, shape, position of the organs and tissues -potentiometer measures translational displacement and rotational displacement |
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Strain gauge |
When a fine wire is stained within its elastic limit, the wires resistance changes due to the change in diameter, length, and resistivity. Can measure very small displacement. |
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Inductive sensor |
Detects metallic objects without contact. The mechanism is that the moving metallic object changes the inductance in a circuit |
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Dielectric Materials |
Cumulative effect of microscopic charge displacements results in net polarization due to seeing up dipole moments or rotating of permanent electric dipoles already present in material. |
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Dipole movement |
A measurement of separation of positive and negative charges |
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Thermocouples |
Temperature difference generates electric potential and vise verse. -reference temperature can be set in 2 ways -direct reading temperature sensor -forcing the reference point to a known temperature, such as 0 degrees Celsius. |
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Electroneurogram |
Measures the conduction velocity and latency of peripheral nerves. Most accurate test to detect and locate peripheral nerve injury |
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Electromyogram |
EMG: evaluates the activation of muscles (action potentials generated my muscle cells) -a compound signal from many motor units' action potential |
