407740 Datasheet, PDF (4/4 Pages) Extech Instruments Corporation. – Digital Sound Level Meter

Battery Replacement
The low battery indication (BAT) appears on the LCD when the 9V battery is nearing
depletion. Reliable readings can be obtained for several hours after the first appearance of
the low battery indication. To replace the battery, slide the battery compartment cover off
the rear of the instrument and replace the 9V battery. Secure the cover before use.
Reference Information
Frequency Weighting Characteristics
Frequency (Hz)
31.5
63
125
250
500
1k
2k
4k
8k
A Weighting
-39.4dB
-26.2dB
-16.1dB
-8.6dB
-3.2dB
0dB
+1.2dB
+1dB
-1.1dB
C Weighting
-3dB
-0.8dB
-0.2dB
0dB
0dB
0dB
-0.2dB
-0.8dB
-3dB
Typical A-Weighted Sound Levels
Tolerance (IEC 651 Type 2)
±3dB
±2dB
±1.5dB
±1.5dB
±1.5dB
±1.5dB
±2dB
±3dB
±5dB
50HP Siren (100')
Jet takeoff (200')
Riveting machine
Subway (20')
Pneumatic drill (50')
Vacuum cleaner (10')
Large store
Small office
Night residential area
Whisper (5'0)
Threshold of hearing
dB
140
130
120
110
100 Chain saw
90 _{Boiler room}
80 _{Freight train (100')}
70 _{Speech (1')}
60 _{Large Office}
50 _Residence
40
30
20 ^{Sound studio}
10
0
Calibration and Repair Services
Extech offers repair and calibration services for the products we sell. Extech also provides
NIST certification for most products. Call the Customer Service Department for information
on calibration services available for this product. Extech recommends that annual
calibrations be performed to verify meter performance and accuracy.
Copyright © 2003 Extech Instruments Corporation
All rights reserved including the right of reproduction in whole or in part in any form.
4
Model 407740 version 1.6 8/05