- Alta precisão - tão boa quanto 20 ppm
- Alta estabilidade - tão boa quanto 5 ppm / ano
- Mais de 55 modelos disponíveis com resistência de 1 mΩ a 121,1 MΩ
- Resolução tão boa 1 mΩ com uma década fixa ou 20 μΩ com um reostato.
- Coeficiente de baixa temperatura - tão baixo quanto 3 ppm / ° C
- Interruptores de contato de liga de prata de alto desempenho
- Resistores hermeticamente selados de baixa indutância
- Nenhuma correção de zero exigida
- Para maior precisão, décadas ≥ 1 Ω podem ser individualmente aparadas
- O padrão de resistência do exército dos EUA
The HARS-LX series is the world's highest accuracy continuously variable decade resistor for the most exacting calibration and test applications.
The HARS-LX substituter is a precision resistance source with excellent characteristics of accuracy, stability, temperature coefficient, and power coefficient. All these features serve to make it a laboratory resistance standard, exceeded in performance only by stand-alone standard resistors.
Hermetically sealed wirewound resistors are used for 1 Ω steps and over. These resistors are carefully conditioned under power and temperature in order to develop the best stability characteristics. Actual experience has shown them to exhibit a storage stability of better than 5 ppm/year, improving as they age. The low-resistance resistors are constructed with resistance wire with a minimum of copper resistance in series to limit temperature coefficient effects.
The resistance substituter has a fixed minimum resistance of 10 mΩ. This is implemented by mechanically limiting the 10 mΩ decade from going below the “1” position. In this manner, no zero resistance subtractions have to be made, and the accuracy given is for the absolute reading.
The HARS-LX series employs completely enclosed dust-tight very low contact resistance switches. They feature solid silver alloy contacts and quadruple-leaf silver alloy wipers which keep switch contact resistance to under 1 mΩ per decade, and more importantly, keep switch contact resistance reproducible, insuring repeatable instrument performance.
High quality gold plated tellurium copper binding posts minimize the thermal emf effects which would artificially reflect a change in dc resistance measurements. All other conductors within the instrument, as well as the solder employed, contain no metals or junctions that contribute to thermal emf problems.
The HARS-LX is designed to allow very convenient maintenance of calibration over time. Most decades can be calibrated without changing components or soldering resistors. The decades for the 100 Ω through 100 kΩ steps are calibrated with convenient trimmers. Trimming of the lower decades is also possible.
With a resolution as low as 1 mΩ and a maximum available resistance of over 12.2 MΩ, the HARS-LX Series may be employed for exacting precision measurement applications requiring high accuracy and stability. They can be used as components of dc and low frequency ac bridges, for calibration, as transfer standards, and as RTD simulators
Resistência por etapa | Resistência total da década | Corrente máxima | poder maximo | Coeficiente de temperatura (ppm / ºC) | Coeficiente de potência (ppm / mW) | Precisão | Estabilidade (±} ppm / ano |
Reostato 100μΩ | 10 m | 2 A | N / D | 20 | 1 | ||
1 m | 10 m | 2 A | N / D | 20 | 1 | 20 ppm + 0,5 mΩ | 20 ppm + 0,5 mΩ |
10 m | 100 m | 2 A | N / D | 20 | 1 | 20 ppm + 0,5 mΩ | 20 ppm + 0,5 mΩ |
100 m | 1 Ω | 2 A | N / D | 20 | 1 | 20 ppm + 0,5 mΩ | 20 ppm + 0,5 mΩ |
1 Ω | 10 Ω | 1 A | 5 W | 20 | 0,4 | 20 ppm + 0,5 mΩ | 20 ppm + 0,5 mΩ |
10 Ω | 100 Ω | 0,33 A | 5 W | 10 | 0,3 | 20 ppm + 0,5 mΩ | 20 ppm + 0,5 mΩ |
100 Ω | 1 kΩ | 0,1 A | 5 W | 3 | 0,1 | 20 ppm + 0,5 mΩ | 20 ppm + 0,5 mΩ |
1 kΩ | 10 kΩ | 33 mA | 5 W | 3 | 0,1 | 20 ppm + 0,5 mΩ | 10 ppm (<5 ppm típico) |
10 kΩ | 100 kΩ | 10 mA | 5 W | 3 | 0,1 | 20 ppm + 0,5 mΩ | 10 ppm (<5 ppm típico) |
100 kΩ | 1 MΩ | 3 mA | 2,000 V | 3 | 0,1 | 20 ppm + 0,5 mΩ | 10 ppm (<5 ppm típico) |
1 MΩ | 10 MΩ | 1 mA | Pico de 2.000 V | 3 | 0,1 | 20 ppm + 0,5 mΩ | 10 ppm (<5 ppm típico) |
10 MΩ | 100 MΩ | Pico de 2.000 V | 15 | 0,2 | 2000 ppm | 50 ppm | |
Resistência de cabos e interruptores | 50μΩ / C | 0,2μΩ / W |
Nenhuma subtração zero necessária
Resistência mínima: 10 mΩ ± 0,5 mΩ; determinado pela posição mais baixa ajustável, "1", da década de 10 mΩ / passo
Repetibilidade da resistência: melhor que 100 μΩ, valor médio de curto prazo