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TYPE: Hand-held
Photometer for measuring illumination intensity and
luminance/
brightness measurements with 10
PhotoSpot attachment.
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TECHNOLOGY: Dual
stage front end op-amplifier, custom sealed hybrid
integrated circuitry, multiple range linear circuit
controlled by microcomputer and custom back-lit liquid
crystal display for highest accuracy and reliability.
Ultra-stable silicon detector.
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COSINE CORRECTED:
Cosine correction is accomplished by using a specially
designed white molded plastic diffuser receptor. The
diffuser provides cosine correction to a high degree of
refinements; thus the detector correctly evaluates the
light intensity regardless of direction.
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COSINE CURVE:
As a beam of light is titled so that it strikes a
surface at an angle, the area covered by the beam
increases. Since the amount of light in the beam remains
constant, the illumination on the surface decreases.
This decrease is proportional to the cosine of the
angle, which the incident beam makes with a
perpendicular to the surface.
The meter reading of a fully cosine-corrected light
meter represents the true illumination of the light
receiver regardless of the angle from which the light
approaches. Cosine error is +/- 1%. See Cosine Corrected
curve for candela II photometer.
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SPECTrAL RESPONSE:
Computer selected glass filters are designed to match the
meter's detector response
to the CIE photopic response (human eye response), which
defines the eye's sensitivity to color. The combined
spectra response is the product of the filter's
transmission and the spectral responsivity of the
detector. The photopic response of the
photometer matches the CIE standard observer curve
response to within 2.5% of the reading when using a
standard tungsten source at 2856°K.
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MEASURING CAPABILITY:
Measures illuminance level in foot-candles (fc) and lux
(lx); luminance measurement with PhotoSpot in
foot-lamberts (fl) or cd/m2.
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Light Sensor: Silicon Photodiode with V (λ)
filter.
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ILLUMINANCE LEVELS:
0.1 to 70,000 fc and
1 to 100,000 lx.
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*LUMINANCE LEVELS:
0.1 to 700,000 fl or cd/m2 (with 1° PhotoSpot accessory).
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MEMORY: Can store up
to two readings in meter memory with store/ recall
switch.
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repeatability: +/-
0.2%
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*CONTRAST RATIO:
Calculates ratio of two readings from l.0:l to 999:I. in
fc or fl.
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*AVERAGING: Average
of multiple readings and or continuous averaging in
foot-candle or foot-lamberts modes are made possible.
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ACCURACY: +/- 5% of
the full-scale value, when measuring blackbody sources.
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CALIBRATION:
Calibration is traceable to the National Institute of
Standard Technology (NIST). NIST traceable calibration
certificate included.
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LAMP:
Electro-luminescent lamp for viewing displayed
measurements at very low light levels.
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TEMPERATURE RANGE:
For maximum accuracy 32° to 130°F or 0° to 55° C.
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POWER SOURCE: One 6
volt battery #A544, PX28L, PX28.
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DIMENSIONS: 5 ½" X 2
½" X 2". Weight 6 ounces.
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WARRANTY: One year
limited warranty.
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All Spectra II-a meters are supplied with
: Photodisc (cosine corrected for key or
directional light), Leather carrying case, Neck-strap,
6-volt battery, NIST traceable calibration and
Certification, Instructional manual and Warranty card.
