3320 2 kV0 pages

3320
Standard Air Capacitors

These standard fixed capacitors are especially built
for high accuracy measurements.
Because of their high insulation resistance, small selfinductance and dissipation factor, these standards may
be used within large frequency ranges.

DESIGN FEATURES
The standard capacitors type 3320 are built as «threepoles» capacitors, as they are equipped with three
electrodes. Solid dielectric used for their construction is
applied to part capacitances C10 and C20 only; those
named C12 having no solid dielectric and being
practically loss-free.

ACCURACY
The value of main capacitance “C12 “ has an accuracy of
0.001 %. The other capacitances’ accuracy is within 0.1
pF.

EQUIVALENT CIRCUTS FOR CAPACITORS
For full accuracy measurements, only the calibrated
capacitance C12 can be used, the partial capacitances C10
and C20 should be eliminated.

As a protection against dust and moisture, capacitors
are enclosed in housings filled with dry air (water
content of dry air: 75...100 ppm resp. 60...80 mg/m3.
We have equipped our standard air capacitors (< 1000
pF) with a drying agent (Silicagel). On the humidity
indicator, mounted at the side, the humidity in the
interior of the instrument can be controlled.
The variable capacitor is constructed as a vacuumcapacitor.
An artificial aging compensates the mechanical
stresses of the plates and supports of the standard
capacitors. The constancy with regard to time is
remarkably increased by this method.
The operating voltage may reach a maximum of 2000
V R.M.S. Each edge of metallic parts is rounded to
avoid dispersion loss

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