ГЭТ 25-79 (НИЛ 2202)
Standard name:
- ГЭТ 25-79 State primary standard of the unit of electrical capacitance
Type of measurement:
- Measurements of electrical and magnetic quantities
Structural division: name НИО\НИЛ:
- Research Laboratory of State Standards in the Field of Measurement of Electrical Circuit Parameters
Guardian Scientist:
- Semenov Yuri Petrovich
Year of creation:
- 1979
Year of re-confirmation:
- 1979 (будет 2026 г.)
Operating principle:
The reproduction of the unit of electrical capacitance is carried out by calculation and experiment based on measurements of the increment in the effective length of the calculated capacitor, which is achieved by mechanically moving the shielding electrode in the space between the main electrodes of the cross-electrode system, satisfying the requirements of the Thompson-Lampard theorem.
Composition of the standard:
- Calculated capacitor with an interferometer in a vacuum block;
- Capacitive transformer bridge
Main metrological characteristics
| Characteristic Name | Value |
|---|---|
| Nominal Capacitance Values at Which Unit Reproduces Values | 0.2 pF |
| Reproduction of the unit with a mean relative square deviation of the measurement result, So, does not exceed | 2 x 10-7 |
| Unexcluded Relative Systematic Error, Θo, does not exceed | 5 x 10-7 |
| The standard uncertainty assessed by Type A, uAo, does not exceed | 1 x 10-7 |
| The standard uncertainty assessed by Type B, uBo, does not exceed | 1.6 x 10-7 |
| Total standard uncertainty | 1.9 x 10-7 |
| Expanded uncertainty (at k=2) | 3.8 x 10-7 |
Verification diagram:
- Heads the state verification scheme for electrical capacitance measuring instruments
Scope of application:
- Radioelectronics, metrology, and instrumentation;
- Electric power and communications systems; space and defense industries; nuclear industry;
- Development and production of electrical insulating materials, etc.
Results of applying the standard:
The unit of electrical capacitance is transferred from the State Primary Standard via the State Secondary Standards in the range:
- from 1 fF to 1 F in the frequency range up to 30 MHz;
- from 1 pF to 100 nF at AC voltage values from 1 V to 230 kV at a frequency of 50 Hz.
The unit of capacitance is also transferred in the field of apparent charge and partial discharge measurements in the range of values from 1 pC to 100 nC.
Measurements of solid dielectric parameters are carried out in the ranges of relative permittivity from 1 to 100 and dielectric loss tangent from 1∙10⁻⁵ to 1 at frequency values from 50 Hz to 10 MHz.
The total number of measuring instruments traceable to ГЭТ 25-79:
Not specified
Ensuring the uniformity of measurements, participation in the CIPM MRA program:
22
- COOMET Comparisons No. 131/DE/95 International Comparisons of 10 pF Capacitance Standards at a Frequency of 1 kHz(1995 г.),
- CCEM-K4 (1996 - 1998); Comparison of capacitor. Capacitance, 10 pF, Frequency: 1592 Hz, участники: NIST; BIPM; BNM-LCIE; CSIRO-NML; MSL; NIM; NMi-VSL; NPL; NRC; PTB; VNIIM,
- APMP.EM-S7 (2003 - 2006); Comparison of capacitors. Capacitance: 100 pF, Frequency: 1.592 kHz, 1 kHz; participants: NMIA; CMS/ITRI; KRISS; NIM; NIMT; NMIJ AIST; NMISA; NML-SIRIM; NPLI; Puslit KIM-LIPI; SCL; SPRING Singapore; VNIIM
- APMP.EM-K4.1 (2004 - 2006); Comparison of capacitors. Capacitance: 10 pF, Frequency: 1592 Hz; participants: NMIA; CMS/ITRI; KRISS; NIM; NIMT; NMC, A*STAR; NMIJ AIST; NMISA; NML-SIRIM; NPLI; Puslit KIM-LIPI; SCL; VNIIM
- COOMET.EM-K4 (COOMET 345/UA/05); (2006 - 2009); Comparison of capacitors. Capacitance: 10 pF, Frequency: 1592 Hz, 1 kHz; participants: SE ""Ukrmetr-teststandard""; BIM; BelGIM; KazStandard; NMIJ AIST; PTB; VNIIM
- COOMET.EM-S4 (COOMET 345/UA/05); (2006 - 2009); Comparison of capacitors. Capacitance: 100 pF, Frequency: 1592 Hz, 1 kHz; participants: SE ""Ukrmetr-teststandard""; BIM; BelGIM; KazStandard; NMIJ AIST; PTB; VNIIM
- CCEM-K4.2017 (2017); Comparison of 10 pF capacitance standards; Optional: comparison of 100 pF capacitance standard. Frequency at 1592 Hz (optional frequency at 1233 Hz) / Voltage 100 V (10 V for optional 100 pF capacitance value); participants: BIPM; LNE; METAS; NIM; NIST; NMIA; NPL; PTB; VNIIM
- Bilateral comparisons with NRC (Canada, 2008)
- Bilateral comparisons 2011, RTB (Germany)
Unique technical installations as part of the standard:
None