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Sensor Technology
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Your choices are...
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Magnetoresistive
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A semiconductor device in which the electrical resistance is a function of the applied or ambient magnetic field.
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Flux-gate / Coil
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The instrument performs a continuous measurement of the differences in the magnetic field at the ends of a vertical rod and plots these on a grid of the area. Widely used in magnetic compass-based navigation applications.
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Hall Effect
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A device that converts the energy stored in a magnetic field to an electrical signal by means of the development of a voltage between the two edges of a current carrying conductor whose faces are perpendicular to a magnetic field.
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Magneto-inductive
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Magnetoinductive sensors incorporate a coil surrounding a ferromagnetic core whose permeability changes within the earth's magnetic field. The coil serves as the inductive element in an oscillator, whose frequency is proportional to the magnetic field being measured. A DC current is provided to set the oscillator into its linear region. Directional change causes a shift in the oscillator frequency, enabling the magnetometer to provide directional and navigational feedback.
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Proton Precession
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Proton precession uses liquids with high densities of hydrogen atoms such as kerosene and methanol. A polarizing DC current is passed through a coil surrounding the sample, creating a high magnetic flux. When the polarizing flux is released, the frequency of the precession of the protons to normal realignment can be used to measure the ambient magnetic field.
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Overhauser / Nuclear Precession
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An electron-rich liquid is combined with hydrogen and subjected to a radio frequency (RF) signal. In the presence of this signal, the unbound electrons in the liquid transfer to the protons of the hydrogen nuclei; the resultant energy transfer polarizes the liquid. The precession frequency is linear with the magnetic flux density and thus can be used to measure it.
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Optically Pumped
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Technology in which a gaseous alkali is polarized with a specific wavelength of light. An RF signal is modulated to determine its optimum depolarization frequency - this depolarization frequency varies with the ambient magnetic field.
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SQUID
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Superconducting quantum interference device (SQUID) is very sensitive to low magnetic fields, and can measure fields as low as the femtoTesla range. Advanced technology used in medical, particularly neuroscientific, applications. Very wide range of magnetic field measurement.
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Other
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Other unlisted, specialized, or proprietary magnetic sensing technology.
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Search Logic:
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All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches.
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Flux Density Measurement:
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The range through which the sensor or instrument is designed to measure; often corresponds to the linear output region of the sensing technology.
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Search Logic:
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User may specify either, both, or neither of the limits in a "From - To" range; when both are specified, matching products will cover entire range. Products returned as matches will meet all specified criteria.
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Allowable Sensor Over-Range
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Overrange specification limits the range of matching products to the specified
range multiplied by a selected overrange factor. This keeps returned matches
close to the range requirement and filters out products with a wider range
than needed. "From", "To", and "Overrange" must all be specified to
activate this option. Example: User specifies a sensor with a range from
0-100. Without overrange specification, sensors with ranges of 0-100, 0-1000,
and -10,000 to +10,000 are returned as matches. An overrange specification
of 50% will filter out any sensors with a full scale range greater than 150.
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Search Logic:
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Matching products will have a range within the specified overrange limit.
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Electrical Output
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The type of electrical signal that will be produced.
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Your choices are...
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Analog Current (4-20 mA)
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Often called a transmitter. A current is imposed on the output circuit proportional to the measurement. Feedback is used to provide the appropriate current regardless of line noise, impedance, etc. Useful when sending signals long distances. 4-20 mA, or any other analog current output
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Analog / Modulated Frequency
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The output signal is encoded via amplitude modulation (AM), frequency modulation (FM), or some other modulation scheme, but the signal is still analog in nature. Examples include sine wave, pulse train, AM, and FM signals
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Analog Voltage
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Output voltage is a simple (usually linear) function of the measurement.
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Serial Interface
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A standard serial digital output protocol such as RS232, RS422, RS485, etc.
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Parallel Interface
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A standard digital output protocol (parallel) such as IEEE 488, printer port, Centronics port, etc.
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Other Digital (TTL, etc)
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Any digital output other than the standard serial or parallel signals. Simple TTL logic signals are an example.
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Switch / Alarm
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The ''output'' is a change in state of a switch or an alarm.
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Other
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Other unlisted, specialized, or proprietary output.
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Search Logic:
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All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches.
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Number of Axes:
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The number of axes of simultaneous magnetic field measurement. Single axis sensors are most common; two and three axis sensors are also available.
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Search Logic:
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User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
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Measurement Features
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Your choices are...
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Direction Measurement
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The instrument measures the direction of the magnetic field. May also indicate "bi-polar" output.
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Magnitude Measurement
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The instrument measures the magnitude of the magnetic field.
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Search Logic:
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All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches.
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Sensing Accuracy:
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The accuracy required of the device.
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Search Logic:
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All matching products will have a value less than or equal to the specified value.
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Resolution:
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The smallest increment of measurement possible with the device.
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Search Logic:
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All matching products will have a value less than or equal to the specified value.
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Bandwidth:
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The frequency range over which the device meets its accuracy specifications. Accuracy is degraded at lower and lower frequencies unless the device is capable of dc response, and at higher frequencies near resonance and beyond, where its output response rolls off. Frequencies in the database are usually the 3dB roll-off frequencies.
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Search Logic:
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All matching products will have a value greater than or equal to the specified value.
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Operating Temperature:
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The temperature range over which the device must operate.
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Search Logic:
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User may specify either, both, or neither of the limits in a "From - To" range; when both are specified, matching products will cover entire range. Products returned as matches will meet all specified criteria.
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Maximum Shock:
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The maximum shock you require the device to survive. Items that are 'typical' may not explicitly give their Max Shock value, so it is a good idea to use this only when working with extremes.
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Search Logic:
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All matching products will have a value greater than or equal to the specified value.
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Maximum Vibration:
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The maximum vibration you require the device to survive. Items that are 'typical' may not explicitly give their Max Vibration value, so it is a good idea to use this only when working with extremes.
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Search Logic:
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All matching products will have a value greater than or equal to the specified value.
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