SR102/103/104 Series


SR102/103/104 Series


Highest accuracy (1 ppm/yr) and stability (±0.5 ppm/yr typical) of any resistance standard

Lowest temperature coefficients (< 0.1 ppm/ºC)

Available in 3 models: 100Ω, 1000 Ω, 10,000Ω.

Has remained the foremost resistance standard, with no equivalent, for over 35 years

5 Year Warranty Included


The primary standard of National Metrology Labs throughout the world

Has remained the foremost resistance standard, with no equivalent, for over 35 years

Oil filled, hermetically sealed; units can be supplied without cases for use in oil bath

ISO/IEC-17025 Accredited Calibration Included

Alpha Beta Measurements Included


The World's Most Stable Resistance Standard



IET continues to manufacturer the SR102 & SR104 to the same exacting specs as esi/Tegam


The esi SR102, SR103 & SR104 are a highly stable (±0.5 ppm/year) and accurate (1 ppm), 100 Ω, 1 kΩ, 10kΩ resistance standards. The SR102, SR103 and SR104 Standards are equipped for five-terminal measurements used for Standard Resistor readings and for Temperature Sensor readings. Individual calibration data, which identifies the Standard Deviation, and the Temperature Characteristics, is supplied with each unit. In addition, each unit is equipped with a thermal well so that the exact temperature of the resistance standard is known. This allows the user to make highly precise, temperature compensated, measurements.


esi SR102 100 Ω Primary Resistance Standard

These resistance standards were designed to provide an important link between rather odd Quantum Hall resistance values and traditional decade resistance values. 100 Ω provides unique reference capability.


esi SR103 1000 Ω Primary Resistance Standard

New resistance standard recently developed to improve the range of primary standards available.


esi SR104 10 KΩ Primary Resistance Standard

This has been the long-standing industry standard for the 10 kΩ. This everlasting standard is the benchmark for high accuracy, stability and low temperature coefficients for calibrations requiring NIST traceability.


The SR102, SR103, and SR104 precision Transportable Resistance Standards are oil filled, hermetically sealed, five-terminal resistance standards designed for precision bench top or oil bath applications.


The long-term stability of these resistance standards is typically less than 0.2 ppm per year and temperature coefficients are less than 0.1 ppm per degree Celsius. This excellent long-term stability and low temperature coefficient is achieved by using matched groups of resistors constructed of the alloy Evanohm-R. The resulting low temperature coefficient allows high performance applications of these standards inside or outside an accurately controlled temperature environment.


Maximum accuracy is calculated as a temperature corrected resistance value. This is accomplished by using the built-in RTD temperature sensor to measure the internal temperature and referencing a temperature correction chart provided with each unit. The measurement accuracy of the built-in RTD thermometer is better than 0.1 degree Celsius.


Very low power coefficients are achieved by using standard resistors constructed with large surface areas like our original Model SR104, 10kΩ standard resistor. The resistors are surrounded by oil to conduct heat generated by the measuring currents out through the stainless steel case.


These characteristics facilitate precise laboratory comparisons without critical environmental controls and are used wherever a need for a very accurate, stable resistor of low temperature coefficient is required.



100 ohm Transportable Resistance Standard: SR-102

1,000 ohm Transportable Resistance Standard: SR-103

10,000 ohm Transportable Resistance Standard: SR-104


For deleted case version add -DC at the end of the part number


Each unit includes:

5 Year Warranty

Built-in temperature sensor

Temperature correction chart

Instruction manual

ISO/IEC 17025 calibration certificate




Stability First 2 years: ±1 ppm/year, thereafter: ±0.5 ppm/year

Temperature coefficient

Alpha: <0.1 ppm/°C at 23°C

Beta (1/2 rate of TC change):<0.03 ppm/°C from 18°C to 28°Ct

No ovens or external power required

Power coefficient<1 ppm/W

Adjustment to nominal ±1 ppm

Measurement uncertainty <0.32 ppm

Max voltage 500 V peak to case

Power rating 1 W (Momentary 100 W overloads will not cause failure)

Thermal emf Thermal emf at the terminals does not exceed ±0.1 μV under normal conditions.

Insulation resistance All terminals maintain a minimum 1012 Ω to ground

Internal temperature sensor 100 Ω, 1 k Ω, or 10 kΩ resistor with 1,000 ppm/°C temperature coefficient. Integral thermometer well is provided for calibration

Hermetic sealing To eliminate the effects of humidity, the resistor is hermetically sealed in oil with metal-to-glass seals. The resistance changes

<±0.1 ppm with normal atmospheric pressure and humidity changes.


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Our partners in other countries

Amtest-TM Kft. (HU) - Attila Polgar Amtest PL (PL) - Dariusz Koziello Amtest-TM ELTH srl (RO) - Bogdan Valcea ADELANTEST Ltd (RUS) - Igor Kozlov GIGA Electronic Ltd. - Danail Georgiev OÜ Est-Doma (EST) Promix Ltd. (UA) - Oleksandr Labuzov Vildoma (LT, LV)

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