Operation
3-1
C H A P T E R
3
Operation
This chapter presents a detailed description of the
operation of the Model 2221. This includes the methods
available for providing power, connecting input and
output cables, parameter selection and adjusting the
gain to obtain the best measurement.
Powering the Model 2221
The Model 2221 can be powered by internal batteries or
from an external DC power source such as the Larson Davis
PSA017, which is supplied as a standard accessory. No
internal or external power is used when the instrument is
switched off.
Internal Battery Power
The Model 2221 is designed to use six AA batteries. This
will provide 40 hours of continuous operation with the
PRM902 Microphone Preamplifier. To insert the batteries,
remove the battery compartment access door as shown in
FIGURE 3-1. The polarity is indicated in the bottom of the
battery compartment.
Battery Replacement
When replacing batteries, the manufacturer strongly
recommends that all cells be replaced with new ones of the
same capacity and type (e.g. all cells Alkaline, NiMH or
NiCd). Failure to do so could lead to cell leakage and
possible damage to the instrument.