User Manual
LT40-en-GB_V3.0 10/17
2
Introduction
CongratulationsonyourpurchaseoftheExtechLT40LEDLightMeterthatmeasureslightintensity
fromwhiteLEDlightsources.TheLT40canalsomeasurelightfromfluorescent,metalhalide,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
CustomerSupport.
Features
OverloadIndication:TheLCDwillshowOL.
LowbatteryIndication.
DisplayUpdateRate:2.5timespersecond.
CosineAnglecorrected.
MeasureswhiteLEDlight.
MeasurestheintensityofilluminationinLuxorfoot‐candles.
Dataholdfreezesdisplayedreading.
Maximum/Average/MinimumreadingHold.
ZeroCalibrationadjustment.
Autopoweroffwithdisablefunction.
Autorange.
Safety
Donotoperatethemeterinenvironmentswherethefollowingarepresent:explosivegases
(ormaterials),combustiblegases(ormaterials),steam,ordust.
PleasereplacethebatteryimmediatelywhenthelowbatterysymbolappearsontheLCD.
Donottouchthemeter’scircuitboardforanyreason;static
electricityorcontamination
coulddamagethesensitivecomponents.
ForIndooruseonly.Thisinstrumentwasdesignedforpollutiondegree2.
OperationAltitude:Upto2000m(7000’).