Model 407750 Version 2.1 February 2004
2
Warranty
EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in parts and
workmanship for one year from date of shipment (a six month limited warranty applies on sensors and
cables). If it should become necessary to return the instrument for service during or beyond the warranty
period, contact the Customer Service Department at (781) 890-7440 ext. 210 for authorization or visit our
website at www.extech.com (click on ‘Contact Extech’ and go to ‘Service Department’ to request an RA
number). A Return Authorization (RA) number must be issued before any product is returned to Extech. The
sender is responsible for shipping charges, freight, insurance and proper packaging to prevent damage in
transit. This warranty does not apply to defects resulting from action of the user such as misuse, improper
wiring, operation outside of specification, improper maintenance or repair, or unauthorized modification.
Extech specifically disclaims any implied warranties or merchantability or fitness for a specific purpose and
will not be liable for any direct, indirect, incidental or consequential damages. Extech's total liability is limited
to repair or replacement of the product. The warranty set forth above is inclusive and no other warranty,
whether written or oral, is expressed or implied.
Introduction
Congratulations on your purchase of the Extech 407750. This device measures sound
level in dB and the measurement range can be set automatically or manually. The
407750 offers selectable frequency weighting (‘A’ and ‘C’) and Time Response (Fast and
Slow). The built-in RS-232 PC interface allows the user to record readings onto a PC in
real-time. Careful use of this meter will provide years of reliable service.
Specifications
Display
Backlit 2000 count LCD with analog bargraph
Display update rate
Main LCD digits: 0.5 seconds; Bargraph: 50mS
Analog Bargraph
1dB steps with 50dB display range
Microphone
Electret condensor (0.5” diameter)
Measurement Bandwidth
31.5Hz to 8KHz
Measurement Range
A weighting: 30 to 130dB; C weighting: 35 to 130dB
6 ranges in 10 dB steps: 30 to 80dB, 40 to 90dB, 50 to
100dB, 60 to 110dB, 70 to 120dB, 80 to 130dB
Accuracy / Resolution
± 1.5dB / 0.1dB
Time response selections
Fast (125ms) and Slow (1 second)
AC and DC Analog outputs
0.707VAC rms at full scale; 10mVDC / dB;
3.5mm output jacks
Standards
Meets ANSI and IEC Type 2
External Calibrator
Extech models 407766 or 407744
Power
9V Battery; 20 hour battery life (typical) with low battery
indication
Dimensions/weight
3.2 x 10.1 x 1.5” (80 x 256 x 38mm) / 8.5 oz. (240g)
