Standard Resistors

Standard Resistors

Here at Rhopoint Components we offer a range of high quality standard resistors for calibration and measurement use. Manufactured by two of the industry leaders on the precision resistor market - Alpha Electronics and Isabellenhuette, our standard resistors are available in several configurations and second-to-none stability and reliability. Browse our range below.

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Alpha ADR 1-Dial Series

The ADR 1-dial resistance box series from Alpha Electronics offers a range of standard resistors which are ideally suited for repetitive daily work. The single dial system means the resistance is easily switched from one value to another. This greatly improves work efficiency and helps to avoid mistakes, which may happen when using a 6-dial decade standard resistor. They are ideally suited for RTD simulation for platinum (Pt) related products and conductive meters.

  • Fully customisable 1-dial resistance box (up to 24 resistance values)
  • Up to 5-digit resistance values on switching contacts may be specified
  • Resistance values available from 1Ω up to 1MΩ
  • Improved work efficiency and elimination of careless mistakes
  • Lightweight, compact size
  • High precision
  • High stability

The resistance elements utilise Bulk Metal® Foil technology and the connections to the rotary switch are made by using 4-terminal junctions. This ensures that high precision, high stability and low temperature coefficients are achieved.

The ADR-1xxx 1-Dial resistance box is fully customisable. Up to 24 different resistance values can be set into the box.

The ADR-1xxx series has a weight of approximately 1kg and dimensions of 100mm x 150mm x 80mm.

The below table gives the full specifications available for the Alpha ADR 1-dial resistance box series:

Alpha ADR 1-Dial Specifications

Tolerance and temperature coefficient varies with resistance values.

£0.00 Ex Tax: £0.00

Alpha ADR 6-Dial Series

The ADR 6-dial decade resistance box series from Alpha Electronics, with 6½ digit readings, features ultra precision resistors, low contact resistance rotary switches, low thermal EMF output terminals and the double shielded construction. There are 5 models of the ADR 6-dial decade resistance box available, each offering different resistance ranges starting from 0.1Ω minimum to 1.111210KΩ maximum up to 10Ω minimum to 11.11110MΩ maximum.

  • 6-Dial decade resistance box
  • Accuracy down to ≤0.005% +2mΩ for some models
  • Temperature coefficient of resistance ≤5ppm /°C
  • Long-term stability in resistance ≤50ppm/year (storage life)
  • Low contact resistance switch and three clip-typed contacts in parallel
  • Low thermal EMF terminal
  • Double electrical shielding protective against noise
  • Maximum power rating of 0.5W

All resistors used in this Decade Resistance Box are from the ultra precision Bulk Metal® Foil resistors manufactured by Alpha Electronics, assuring high stability over time and environment change.

The rotary switches have very low contact resistance which is achieved by connecting three clip-type contacts in parallel. This method also ensures a higher mechanical reliability. Low thermal EMF output terminals use a low thermal resistance rectangular wire circuit configuration. A double shielded construction inhibits interference of environmental noise.

The ADR 6-dial resistance box series has a weight of approximately 4.5kg and dimensions of 430mm x 140mm x 99mm.

The below table gives the full specifications for each model available of the Alpha ADR 6-dial decade resistance box series:

Alpha ADR 6-Dial Specifications

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Alpha ASR Series

The ASR series from Alpha Electronics is an extremely stable standard resistor. It utilises their Ni/Cr alloy Bulk Metal® Foil technology for the resistive elements, which helps provide high stability and a low temperature coefficient. With the extreme stability of this resistor relative to temperature change, the ASR can be used in air without the need of an oil bath or critical environmental temperature control, eliminating added operation and maintenance costs.

  • Standard Resistor
  • Excellent long-term stability of resistance, less than 3 ppm/year
  • Low temperature coefficient, less than 0.2 ppm/°C
  • Resistance options between 1Ω to 10MΩ available
  • Excellent AC characteristics due to Bulk Metal® Foil technology
  • Compact construction designed for simple operation and storage
  • Power rating of 0.1W (0.5W for the ADR-1R0 model)
  • Maximum working temperature of +50°C
  • Operating temperature range of 0 to +50°C
  • Storage temperature range from -10°C to +60°C

Due to Alpha Electronics long-term experience in developing and enhancing ultra-stable Bulk Metal® Foil technology, they are able to provide products with consistency of performance under strict quality control. The ASR is designed to be used in a wide range of environments; from making precise measurements on the production floor, to providing corporate traceability as a calibration and reference standard.

The resistors are mounted within a compact and sturdy box. A cover is provided to protect the resistors and connection terminals from damage during transport and storage.

The ASR series has a weight of approximately 2.5kg and dimensions of 155mm x 97mm x 112mm.

The below table gives the full specifications for each model available of the Alpha ASR series:

Alpha ASR Specifications

* Power = Power rating.

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Alpha ATS Series

The ATS series from Alpha Electronics is a resistance transfer standard used to calibrate working standard resistors by using a primary resistor. The ATS series consists of 10 high precision resistors of the same nominal value (R) which are connected in series known as Haymon bridge construction. The ATS unit can be used as a standard resistor due to the low temperature coefficient and high stability features of Alpha Electronics Bulk Metal® foil technology, ensuring very tight matching accuracy.

  • Resistance transfer standard for calibrating standard resistors
  • Uses Bulk Metal® Foil as a resistive element
  • Usable in air without the need of an oil bath due to its superior temperature coefficient
  • Very tight matching accuracy
  • Excellent long-term stability
  • Power rating of 0.01W per resistor element, 0.1W per unit
  • Working temperature range of +23°C ±10°C
An extremely high precision resistance ratio of 1:100 maximum is obtained by using either the ATS-LC lead compensator or the ATS-SC shorting bar. These configurations consist of:
  • connecting the 10 resistors in parallel (1/10*R)
  • connecting the 10 resistors in series (10*R)

The ATS-LC lead compensator and the ATS-SC shorting bar are available as additional options.

The ATS series has a weight of approximately 3kg and dimensions of 180mm x 70mm x 332mm.

The below table gives the full specifications for each model available of the Alpha ATS series:

Alpha ATS Specifications

£0.00 Ex Tax: £0.00

Alpha ATV Series

The ATV series from Alpha Electronics is a current / voltage (I/V) conversion adaptor used to accurately measure current using a voltage meter. Its small, lightweight construction enables it to be easily attached directly to a voltage meter for ease of operation.

  • Current / voltage conversion adaptor
  • Compact size
  • Lightweight
  • Full resistance range available from 1Ω to 100kΩ
  • Temperature coefficient of ±2.5 ppm/°C
  • ±0.1% accuracy
  • Maximum working current of up to 0.5A (ATV-1R0 1Ω model)
  • Power rating of 0.1W (0.25W for the ATV-1R0 model)

Each model corresponds to a set resistance value and maximum working current.

The below table gives the full specifications for each model available of the Alpha ATV series:

Alpha ATV Specifications

£0.00 Ex Tax: £0.00

Alpha CSR Series

The CSR working standard resistor series from Alpha electronics uses Bulk Metal® foil resistance elements, which have the same excellent stability and low temperature coefficient of resistance as the ASR series. Alpha's Bulk Metal® foil offers a precision that cannot be matched by any other resistance material. The CSR series can be customised to any resistance value from 0.001Ω up to 100MΩ.

  • Standard Resistor
  • Wide resistance range available from 0.001Ω to 100MΩ
  • Custom resistance values are available on request
  • Compact construction designed for simple operation and storage
  • Terminals aligned in a single row for easier wiring and placement
  • Low cost, high performance
  • Power rating of up to 0.5W (CSR-1N0, CSR-10N and CSR-R10 models)
  • Working temperature range of +18°C to +28°C
  • Storage temperature range of 0 to +50°C

The CSR is designed for equal ease of use either in laboratory conditions or on the production floor. The construction of the CSR series is designed to give ease of transport and storage, and can be used in normal air environments without the need for oil bath submersion.

The CSR series has a weight of approximately 300g and dimensions of 100mm x 65mm x 66.5mm.

The below table gives the full specifications for each model available of the Alpha CSR series:

Alpha CSR Specifications

£0.00 Ex Tax: £0.00

Alpha LSR Series

The LSR high power standard resistor series from Alpha Electronics was developed to meet the requirements of high current / low resistance applications. Bulk Metal® Foil resistive elements are used to ensure the best long-term stability and lowest temperature coefficients are achieved. The enclosure is manufactured from perforated aluminium to allow effective air flow and temperature dissipation during high power operation. The LSR series is designed to be used in air without oil bath submersion or additional cooling.

  • High power standard resistor
  • Long-term stability better than 20 ppm/year
  • Temperature coefficient of ±2.5 ppm/°C
  • Temperature efficient design to control self-heating
  • Excellent AC characteristics due to Bulk Metal® Foil technology
  • Compact construction designed for simple operation and storage
  • Maximum power rating of 4W available
  • Working temperature range of +18°C to +28°C
  • Storage temperature range of 0 to +50°C
  • 4-terminals

LSR high power standard resistor series is suitable for a range of applications such as high precision measurement, corporate metrology calibration labs and references for precision power supplies.

The 1mΩ version has an option to change the terminal knobs for 4W (63A) power measuring capabilities. The P at the end of the model number denotes the high power option.

The LSR series has a weight of approximately 0.6kg and dimensions of 140mm x 90mm x 90mm.

The below table gives the full specifications for each model available of the Alpha LSR series:

Alpha LSR Specifications

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Alpha MSR Series

The MSR series from Alpha Electronics offers a compact standard resistor suitable for the calibration of low resistance milliohm meters. The internal construction and connection terminals are designed to optimize AC characteristics and minimize the effect of thermoelectromotive force. Alpha's Bulk Metal® Foil resistive elements are used to ensure the best long-term stability and lowest temperature coefficients are achieved. The MSR calibration resistor is a cost effective and simple product, offering both high stability and low temperature coefficient.

  • Compact standard resistor for low resistance calibration
  • Compact, lightweight, portable and easy to operate
  • Excellent performance versus cost ratio
  • Resistive pattern designed to minimize difference performance between AC and DC
  • Standard resistance values of 0.001Ω, 10mΩ and 100mΩ available as well as custom resistances
  • Maximum working voltage of up to 0.01V (model MSR-1N0)
  • Maximum working current of up to 10A (model MSR-1N0)
  • Maximum power rating of 0.1W
  • Maximum working temperature of +50°C
  • Storage temperature range of 0 to +50°C
  • 5 terminals

The MSR is a compact standard resistor suitable for daily calibration of milliohm meters, etc. Although the MSR series is a low cost, easy to use product, it offers both high stability and low temperature coefficient. The MSR is most suitable as a standard resistor to be used on the job site.

The MSR series has a weight of approximately 150g and dimensions of 50mm x 44mm x 65mm.

The below table gives the full specifications for each model available of the Alpha MSR series:

Alpha MSR Specifications

£0.00 Ex Tax: £0.00

Alpha USR-SF Series

The USR-SF series from Alpha Electronics is an ultra-stable primary standard resistor which is an enhanced version of the USR / ASR series. The ultra-stable resistive element utilises the new generation stress-free Bulk Metal® foil technology, which results in an extremely low temperature coefficient of ±0.05 ppm/°C at +23°C ±5°C. This performance is unique to Alpha Electronics throughout the world.

  • Ultra-stable primary standard resistor
  • Utilises new generation stress-free Bulk Metal® foil technology
  • Long-term stability: 0.5 ppm/yr (0.2 ppm/yr typical)
  • Temperature coefficient: less than ±0.05 ppm/°C at +23°C ±5°C
  • Excellent humidity coefficient of resistance of less than 0.1 ppm/% RH
  • Excellent pressure coefficient of resistance of less than 0.001 ppm/hPa
  • Available in a wide range of resistances values (1Ω, 10Ω, 25Ω, 100Ω, 1KΩ and 10KΩ)
  • Maximum power rating of 1W
  • Working temperature range of +18°C to +28°C
  • Storage temperature range of 0 to +50°C
  • 5 terminals

The stress-free resistance element eliminates stress factors by using a special treatment process, and is encapsulated in a specially-designed ceramic case to protect against humidity, oxidation and vibration during transportation. Alpha's Bulk Metal® foil construction provides excellent AC characteristics, superior in performance compared to conventional wire-wound standard resistors.

The USR-SF, with its extreme long-term stability and low TCR, can be used in normal air environments, which eliminates the additional cost of operating and maintaining oil baths.

The USR-SF series has a weight of approximately 2.2kg and dimensions of 155mm x 97mm x 112mm.

The below table gives the full specifications for each model available of the Alpha USR-SF series:

Alpha USR-SF Specifications

* Rated power will be different for future additional lower resistance values

£0.00 Ex Tax: £0.00

Isabellenhütte IKL-F Series

The IKL-F series from Isabellenhütte is a high current resistor for calibration. Developed in order to meet the users requirements for compact, high quality, easily mountable and calibration resistors, for the measurement of very high and permanent currents but also can secure detection of extremely small DC currents in the mA range. The IKL-F series from Isabellenhütte offers 4 wire resistors which are completely pluggable, the precision alloy Manganin® guarantees a low TCR and a high stability. Supplied with a DKD calibration certificate to meet the highest requirements of calibration measurements.

  • High current resistors for calibration
  • Resistance range 0.001Ω to 1Ω
  • Standard resistance value 0.006Ω
  • Current (pulse) 10A to 100A
  • Low TCR value ±10 ppm/K (from +20°C to +60°C)
  • Applicable temperature range from 0°C to +80°C
  • Tolerance of ±0.05%
  • Long term stability <0.05%
  • 4 wire resistors completely pluggable
  • High stability
  • Detection of small DC currents in the mA range
  • DKD calibration certificate

The below table gives an overview of the specifications for the Isabellenhütte IKL-F series:

Isabellenhütte IKL Specifications

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Isabellenhütte IKL-G Series

The IKL-G series from Isabellenhütte is a high current resistor for calibration. Developed in order to meet the users requirements for compact, high quality, easily mountable and calibration resistors, for the measurement of very high and permanent currents but also can secure detection of extremely small DC currents in the mA range. The IKL-G series from Isabellenhütte offers 4 wire resistors which are completely pluggable, the precision alloy Manganin® guarantees a low TCR and a high stability. Supplied with a DKD calibration certificate to meet the highest requirements of calibration measurements.

  • High current resistors for calibration
  • Resistance range 100µΩ to 0.001Ω
  • Standard resistance value of 250µΩ
  • Current (pulse) 30A to 200A
  • Low TCR value ±10 ppm/K (from +20°C to +60°C)
  • Applicable temperature range from 0°C to +80°C
  • Tolerance of ±0.05%
  • Long term stability of <0.05%
  • 4 wire resistors completely pluggable
  • High stability
  • Detection of small DC currents in the mA range
  • DKD calibration certificate

The below table gives an overview of the specifications for the Isabellenhütte IKL-G series:

Isabellenhütte IKL Specifications

£0.00 Ex Tax: £0.00

Isabellenhütte IKL-H Series

The IKL-H series from Isabellenhütte is a high current resistor for calibration. Developed in order to meet the users requirements for compact, high quality, easily mountable and calibration resistors, for the measurement of very high and permanent currents but also can secure detection of extremely small DC currents in the mA range. The IKL-H series from Isabellenhütte offers 4 wire resistors which are completely pluggable, the precision alloy Manganin® guarantees a low TCR and a high stability. Supplied with a DKD calibration certificate to meet the highest requirements of calibration measurements.

  • High current resistors for calibration
  • Resistance Range 5µΩ to 100µΩ
  • Standard values 5µΩ, 30µΩ and 60µΩ,
  • Current (pulse) of 100A to 2000A
  • Low TCR of ±10 ppm/K (from +20°C to +60°C)
  • Applicable temperature range from 0°C to +80°C
  • Toleranceof ±0.05%
  • Long term stability of <0.05%
  • 4 wire resistors completely pluggable
  • High stability
  • Detection of small DC currents in the mA range
  • DKD calibration certificate

The below table gives an overview of the specifications for the Isabellenhütte IKL series:

Isabellenhütte IKL Specifications

£0.00 Ex Tax: £0.00