DESCRIPTION
For measurement at 100 pF and
below, a three terminal connection
increases the accuracy by eliminating
the uncertainty in the measurement
introduced by the capacitances
between the capacitor terminals
and ground.
The type 1403 Standard Air Capacitors
are stable, three-terminal
standards in decimal values from
0.001 to 1000 pF. Their terminals
are arranged to plug directly into the
UNKNOWN terminals of the Type
1620 Capacitance Bridge or equivalent
such as AH2500A Ultra Precision
Capacitance Bridge.
The three largest sizes are similar
in construction to the Type 1404.
The smaller capacitance units
are made up of two plates, with
a grounded plate between them;
an aperture in the grounded plate
determines the magnitude of the
direct capacitance.
Dielectric losses are extremely
low as there is no solid dielectric
in the direct-capacitance fi eld.
All have shielded terminals, both
of which are connected to the
case.