within
the
operating range of 3.5 V
to
5 V. If
the
needle moves into
the
red
zone
the
voltage has fallen below
the
limits and
the
batteries should be
replaced. This indicator permits observation
of
battery degradation as it
occurs.
Output
Control Knob
This knob controls what appears
at
the
outputs
of
the
device.
In
the
"Off"
position there
is
no power
in
the unit and therefore no output.
In
the
l1position
the
signal from
"Input
1"
appears
at
"Output
1"
and
the
signal
from
"Input
2"
at
"Output
2".
In
the X,position the signal from
"Input
1"
appears
at
"Output
2"
and
the
signal from
"Input
2"
appears
at
"Output
1". This feature allows ease
in
making comparison measurements.
Outputs 1 and 2
These terminals accept the standard JP
0018
connector and carry one
or
the other of
the
two input signals depending on
the
setting
of
the
"Output
Control Knob".
Inputs 1 and 2
These terminals are the standard B & K microphone sockets accepting
the JP 0023 seven pin plug. They carry
the
ground, polarization voltage,
heater voltage {when present, see Section Rear Panel), etc., for powering
the
microphone {or accelerometer)
Type
2619 preamplifier. They also carry
the
signal from
the
transducer.
Thumb Screw {Polarization Voltage Selection)
This screw releases the.
bottom
plate
of
the
unit. When this plate
is
removed
the
printed circuit card
is
revealed. On this card
is
a small rotary
two position switch for selecting
the
polarization voltage desired. {Fig.2.2).
5
