Velleman DVM401 Notice D'emploi page 5

4. Operation
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
01.07.2009
DVM401
wavelength (Nm)
5
Rev. 02
spectral sensitivity
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