8
1404 Series
8
Maintenance
4.3 Calibration Procedure with
GenRad 1620 or AH2500A/
AH2700A Capacitance Bridge
To calibrate an 1404 unit, proceed as follows:
1. 1404 capacitors with bnc connectors should
have the shield disconnected at the
HI
termi-
nal to minimize stray capacitance. The shield
on the LO terminal should be maintained.
This connection mimics the connection on the
IET/GenRad 1404 Standard Capacitor.
2. Determine and employ proper metrological
practices.
Allow a confi dence band for the uncer-
tainty of the measuring instrument and
setup.
3. Determine the allowable drift limits for the
capacitance reading.
<20 ppm/year
4.
Confi rm that the readings fall within these
drift limits, allowing for the uncertainty band.
If the reading falls outside the limits,
it has to be repaired by IET or another
qualifi ed facility
Summary of Contents for 1404 Series
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