Extech Instruments LT40 User Manual page 2

Introduction
Congratulations on your purchase of the Extech LT40 LED Light Meter that measures light intensity
from white LED light sources. The LT40 can also measure light from fluorescent, metal halide, high‐
pressure sodium, and incandescent sources, for reference only (unspecified accuracy). The LT40
can measure light up to 40,000 Fc (400,000 Lux). This instrument is shipped fully tested and
calibrated and, with proper use, will provide years of reliable service. Please visit our website
(www.extech.com) to check for the latest version of this User Guide, Product Updates, and
Customer Support.
Features
Safety
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 Overload Indication: The LCD will show OL.
 Low battery Indication.
 Display Update Rate: 2.5 times per second.
 Cosine Angle corrected.
 Measures white LED light.
 Measures the intensity of illumination in Lux or foot‐candles.
 Data hold freezes displayed reading.
 Maximum/Average/Minimum reading Hold.
 Zero Calibration adjustment.
 Auto power off with disable function.
 Auto range.
 Do not operate the meter in environments where the following are present: explosive gases
(or materials), combustible gases (or materials), steam, or dust.
 Please replace the battery immediately when the low battery symbol appears on the LCD.
 Do not touch the meter's circuit board for any reason; static electricity or contamination
could damage the sensitive components.
 For Indoor use only. This instrument was designed for pollution degree 2.
 Operation Altitude: Up to 2000m (7000').
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