Extech Instruments 407744 Manuale Utente
3 407744 & 407766-EN v5.3 1/14
Operation
Theory of Operation
The 407744 sound level calibrator generates a 94dB sine wave at 1 KHz. The 407766 generates a
94dB and a 114dB sine wave at 1kHz. When a microphone from a sound level meter is inserted into
the calibrator, the sound level meter picks up the signal and displays the signal in dB (decibel) units.
The sound level meter should be adjusted (if necessary) to match the calibrator’s output signal as
closely as possible (see diagram).
94dB and a 114dB sine wave at 1kHz. When a microphone from a sound level meter is inserted into
the calibrator, the sound level meter picks up the signal and displays the signal in dB (decibel) units.
The sound level meter should be adjusted (if necessary) to match the calibrator’s output signal as
closely as possible (see diagram).
Procedure
1. Insert the microphone into the calibrator’s microphone cavity as shown;
ensure that it is fully inserted. Use the ½” microphone adaptor (supplied
attached to the calibrator) for ½” microphones.
attached to the calibrator) for ½” microphones.
2. On the 407744, slide the function switch to the ‘I’ (Power On) position. As
soon as the unit is powered, the calibration tone is generated. On the
407766, slide the function switch to the 94dB or the 114dB position as
desired. The calibrator generates its signal as soon as the switch is set.
407766, slide the function switch to the 94dB or the 114dB position as
desired. The calibrator generates its signal as soon as the switch is set.
3. Read the sound level meter’s display. The sound level meter should read
94dB or 114dB depending on the calibrator’s setting. If the sound level
meter does not match the calibrator’s signal (within specification), adjust it
as explained in the Operation section (typically a front or side-panel pot
adjustment). Refer to diagram at right.
meter does not match the calibrator’s signal (within specification), adjust it
as explained in the Operation section (typically a front or side-panel pot
adjustment). Refer to diagram at right.
4. Slide function switch to the OFF position, and remove the microphone.
Battery Check
On the 407744, check the condition of the battery by moving the function switch to the ‘Battery test’
position. The Battery status LED should illuminate if the battery is OK. If it does not light, replace the
9V battery. On the 407766, the POWER-ON / LOW-BATTERY LED glows brightly when the battery
is fresh and dimly when the battery is weak.
position. The Battery status LED should illuminate if the battery is OK. If it does not light, replace the
9V battery. On the 407766, the POWER-ON / LOW-BATTERY LED glows brightly when the battery
is fresh and dimly when the battery is weak.
Battery Replacement
Lift off battery compartment cap (shown in the Description section) to access the two (2) 9V
batteries. Remove the batteries and replace with new alkaline 9V batteries. Replace the cap.
batteries. Remove the batteries and replace with new alkaline 9V batteries. Replace the cap.
You, as the end user, are legally bound (EU Battery ordinance) to return all used
batteries, disposal in the household garbage is prohibited! You can hand over your
used batteries / accumulators at collection points in your community or wherever batteries /
accumulators are sold!
batteries, disposal in the household garbage is prohibited! You can hand over your
used batteries / accumulators at collection points in your community or wherever batteries /
accumulators are sold!
Disposal: Follow the valid legal stipulations in respect of the disposal of the device at the
end of its lifecycle
end of its lifecycle