CHAPTER 2
Operation
7
P
s
is the preamplifier sensitivity in mV/pC or mV/mV
V
0
is the voltage output from the preamplifier measured in millivolts when the
accelerometer is vibrated at the reference acceleration
A
0
is the reference acceleration level: 10 ms
–2
for Type 4294 or 3.16 ms
–2
for
Type 4294 002
7) If a calibrated voltmeter and a conditioning amplifier are used to measure the transducer
charge sensitivity, then an arbitrary mV/unit out range may be selected on the preamplifier.
Multiplication of the mV/unit out setting be the reference acceleration level gives the
correct voltmeter reading. It is then a simple step to adjust the transducer sensitivity dials
on the conditioning amplifier so that the correct voltage reading is displayed by the
voltmeter. The dials on the preamplifier with then indicated the accelerometer sensitivity,
S
c
.
8) Any significant departure of the calculated value of S
c
from that shown on the transducer
calibration chart is indicative of a faulty transducer.
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