BRUEL & KJAER 2225 User Manual

The polarities should be as indicated on the case. New cells will provide about 30 hours
continuous operation in normal conditions, or 1 0 hours in direct sunlight. Batteries
should be replaced whenever the battery condition indication, obtained by pressing
RESET (BATI.), falls below the region indicated on the display.
It is recommended that only alkaline batteries, such as those supplied with the instru-
ment, are used.
3.3. MOUNTING THE MICROPHONE
The microphone is screwed directly onto the adaptor, using light finger torque. The as-
sembly may then be plugged directly into the sound level meter via its 5 pin DIN plug
(see Fig . 3.2) or connected via a 3m or 10m extension lead available under order num-
bers AO 0185 and AO 0186 respectively. The microphone end of the extension lead
has a threaded attachment to enable it to be connected directly to a standard tripod
screw. This arrangement allows the operator to be close to the sound level meter for
reading purposes, while at the same time enabling him to be well away from the micro-
phone, and therefore not influence the sound field.
----::- ::
--- - ~
Fig. 3. 2. Microphone, adaptor and connection to the sound level meter
3.4. CALIBRATION
The Sound Level Calibrator Type 4230 is recommended for acoustical calibration of the
whole instrument, including microphone. The 4230 is basically a miniature loudspeaker
with a stabilised output of 94 (± 0,25) dB (re. 20 x 10-
6
Pa.) at 1 kHz. The calibration
procedure is as follows:
1. Mount the microphone, switch power on and press RESET. BATI. to check the bat-
teries of the Sound Level Meter. The instrument will switch off automatically two
minutes after a Reset occurs.
2. Fit the Sound Level Calibrator with the half-inch adaptor. (B & K part No. DB 0311)
3. Remove the dust cap or windshield from the microphone and fit the calibrator over
the microphone so that it seals properly. See Fig.3.3.
4. Set the RANGE SELECTOR to the "80 to 1 20 dB(A)" range and FUNCTION SELEC-
TOR to "Fast" detector setting.
5. Remove the small, push-fit, plastic plug on the top front of the instrument to gain ac-
cess
to the sensitivity adjustment potentiometer.
9

BRUEL & KJAER 2225 Specifications

General

Brand	BRUEL & KJAER
Model	2225
Category	Measuring Instruments
Language	English