ENDEVCO 2680
INSTRUCTION MANUAL
IM2680
Page B-1
APPENDIX B:
GAIN ADJUSTMENT
1.
THEORETICAL GAIN ADJUSTMENT
Gain is limited by the full-scale output requirement. The gain setting along with the sensitivity of
the Transducer will determine the overall sensitivity of a system (Accelerometer/Cable/Charge/
Amplifier).
A measurement system incorporating a 2680 Series Charge Amplifier and a Transducer has a
maximum sensitivity (As) determined by the formula:
Eo
_________
As = Desired FS
where
As = Peak system sensitivity in mV/g pk
Eo = Charge amplifier's peak full-scale output in mV pk
FS = Charge amplifier's desired peak full scale output in g pk
The Amplifier's Charge Gain Setting (Aq) is computed by:
As
Aq = ______
Sq
where
Aq = Amplifier's Charge Gain setting in mV/pC
Sq = Transducer's Charge Sensitivity in pC/g
As an example, suppose a system consisting of an Endevco Model 2680 Series Charge Amplifier
(which has a 2.5 V pk, or 2500 mV pk full-scale output) and an Endevco Model 2271
Accelerometer is used as a system to measure ±50 g full scale pk. The formula used to
determine the desired system sensitivity in mV/g is:
Eo (in mV pk)
A s = _____________
Desired FS (g pk)
= /F (25mV, 50 g)
= 50 mV/g pk
With the Charge Sensitivity (Sq) of the Accelerometer given as 13 pC/g, the Gain Setting of the
Charge Amplifier is:
A s
As = ____
Sq
= 2500 mV
50
= 50 mV/g pk
