Velleman DVM401 Kurzanleitung Seite 3

6. Function switch : Select temperature, humidity, sound level and luminous intensity with this switch.
7. Microphone : built-in electret condenser microphone
8. Photo detector : long-life silicon photo diode is built in
9. Sensor for humidity measurements is built-in
10. Temperature terminal : insert the temperature probe in this terminal
5. Operating Instructions
a) Measuring Sound Levels
1. Place the function switch in the dB position.
2. Hold the microphone at a horizontal angle to the source to be measured.
3. Press the SELECT button to select A & dB, C & dB, Lo & dB or Hi & dB.
4. Both the A- and C-weighting curves have a frequency range between 30Hz and 10KHz
5. The fast response is ideal to measure short bursts of sound and peak values.
6. The sound level is displayed.
Note : strong winds (> 10m/sec.) can influence your measurements. Use the included windscreen when this
happens.
b) Measuring Light Levels
1. Place the function switch in the LUX-position
2. Hold the detector at a horizontal angle to the source to be measured.
3. Press SELECT to select the range : 20, 200, 2000, 20000Lux.
4. Read the nominal value from the display.
5. The overrange indication ("1") is displayed if the input signal exceeds the range limit. Select a higher range.
6. Remove the photo detector from the light source when the measurement is completed.
7. The spectral sensitivity of this device is very similar to the CIE curve (International Commission on Illumination)
depicted below :
relative sensitivity
relatieve gevoeligheid
sensibilité relative
sensibilidad relativa
relative Empfindlichkeit
DVM401
spectral sensitivity
spectrale gevoeligheid
sensibilité spectrale
sensibilidad espectral
spektrale Empfindlichkeit
Wavelength (Nm)
Golflengte (Nm)
Longueur d'onde (Nm)
Longitud de la onda
Wellenlänge
3