GENERAL
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Brand | IET Labs, Inc |
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Sub Categories | Lab tools |
Application | Standard Capacitor |
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Uses:
The GenRad 1404 Series standard capacitors are the standard of choice in metrology labs, and still used today by National Metrology Laboratories (NMI) around the world.
These capacitors have been designed as primary reference standards of capacitance with which working standards can be compared.
The 1404 Standard Capacitors have also been used as part of a system for generation of low dc currents as seen in the paper Generation of reference dc currents at 1 nA level with the capacitance-charging method.
In combination with an accurately known external resistor, the GenRad 1404 standard capacitors becomes a standard of dissipation factor.
IET Labs continues to manufacture the 1404 Capacitance Standards to the same exacting specifications as GenRad did in 1963.
All critical parts of the plate assembly are made of Invar for stability and low temperature coefficient.
After heat cycling and adjustment, the assembly is mounted in a heavy brass container, which, after evacuation, is filled with dry nitrogen under pressure slightly above atmospheric and sealed.
The container is mounted on an aluminum panel and protected by an outer aluminum case. Each capacitor is subjected to a series of temperature cycles to determine hysteresis, temperature coefficients and to stabilize the capacitance.
More information on the design, frequency characteristics can be found at GenRad Experimenter 1404 Capacitance Standard
Each 1404 Capacitance Standard is then calibrated using an Andeen and Hagerling AH2700A Capacitance Bridge using direct measurements which are calibrated traceable to the SI, through a National Metrology Institute (NIST) with a CMC1 as good as 5.5 μF/F.
IET Labs can also provide accredited calibration using the GenRad 1620 via transfer measurements using 1404 capacitance standards that are calibrated traceable to the SI, through a National Metrology Institute mainly NRC in Canada with CMC1 as good as 4.8 μF/F.
See our Capacitance Calibration page for more information on capacitance calibration.
MODELS
GenRad / General Radio 1404-10nF (10,000 pF) Recently Released
GenRad / General Radio 1404-A (1000 pF) Primary Standard Capacitor
GenRad / General Radio 1404-B (100 pF) Primary Standard Capacitor
GenRad / General Radio 1404-C (10 pF) Primary Standard Capacitor
1See ISO-17025 Scope of Accreditation (A2LA) for our complete list of accredited calibration capabilities.
SPECIFICATIONS
Calibration: A certificate of calibration is supplied with each capacitor, giving the measured direct capacitance at 1 kHz, 30 Vac and 23° ±1°C. The measured value is obtained by a comparison to a precision better than ±1 ppm with working standards whose absolute values are known to an accuracy of ±5 ppm, determined and maintained in terms of reference standards periodically traceable to an SI.
Adjustment Accuracy: The capacitance is adjusted before calibration with an accuracy of ±5 ppm to a capacitance about 5 ppm above the nominal value relative to the capacitance unit maintained by the reference standards.
Temperature Coefficient of Capacitance: A measured value with and accuracy of ±1 ppm/°C is given on the certificate.
Model | Temperature Coefficient |
1404-A
1404-B |
2 ±2 ppm/°C from -20°C to +65°C |
1404-C | 5 ±2 ppm/°C from -20°C to +65°C |
1404-5 nF
1404-10 nF |
4 ±2 ppm/°C from -20°C to +65°C |
Temperature Cycling: For temperature cycling over range from -20°C to +65°C , hysteresis (retraceable) is less than 20 ppm at 23°C.
Stability:
Model | Long Term Drift | Max Change with Orientation |
1404-A
1404-B 1404-C |
less than 20 ppm per year | 10 ppm and completely reversible |
1404-5 nF
1404-10 nF |
less than 40 ppm per year | 10 ppm and completely reversible |
Dissipation Factor: Less than 10-5 at 1 kHz.
Residual Impedance:
Model | CH | CL | L |
1404-A
1404-B 1404-C |
30 pF | 28 pF | 0.05 µH |
1404-5 nF
1404-10 nF |
130 pF | 127 pF | 0.1 µH |
Max Voltage:
Model | Maximum Voltage |
1404-A
1404-B 1404-C |
750 V peak |
1404-5 nF
1404-10 nF |
100V peak |
Terminals: Two BNC coaxial connectors (legacy locking G874 coaxial connectors are available). Outer shell of one connector is ungrounded to permit capacitor to be used with external resistor as a dissipation factor standard.
Mechanical:
Model | Dimensions | Weight |
1404-A
1404-B 1404-C |
(16.9 cm H x 17.2 cm W x 20.4 cm D
(6.63″ x 6.75″ x 8″) |
3.9 kg 8.5 lb
6.4 kg 14 lb Shipping |
1404-5 nF
1404-10 nF |
(23 cm W x 23 cm H x 22 cm D)
9″ x 9″ x 8.5″ |
16 kg 35 lb
18 kg 40 lb Shipping |
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