Technical Specifications; Measurement Principle - Velleman DVM77N Mode D'emploi

5. Technical Specifications

Measurement Range -20°C ~ 270°C (-4°F ~ 518°F)
Accuracy +/- (2% of rdg + 3°C/6°F)
Ambient Temperature Measurement Range 0°C ~ 50°C (32°F ~ 122°F)
Resolution 1°C/1°F
Emissivity 0.95
Distance-to-Spot Ratio 6:1
Overrange Indication "OL" or "-OL"
Auto Power-Off 20s
Power Supply 2 x AAA battery (order code LR03C, incl.)
Dimensions 94 x 59 x 28mm
Weight 75g

6. Measurement Principle

Non-contact thermometers detect the infrared ray of an object, focus the infrared energy of the object onto a sensor through a lens, and
transfer the surface temperature into an electric signal. A microcomputer calculates and displays the measurement temperature on the LCD.
The laser is only used to aim the thermometer.
7. Operation
• How to Measure an Object's Temperature
Point the infrared sensor towards the object and press the SCAN button. The thermometer emits a laser beam. Read the measured
temperature value from the LCD display. Release the SCAN button. The thermometer will automatically power off after 20 seconds. Refer to
"8. D:S Ratio" for accurate results.
DVM77N 4 VELLEMAN