Cropico RBB

High accuracy decade resistance box with versatile wide ohm range

  • 5 and 6 decades available
  • Highest Range 11.1111 Mega ohm
  • Smallest Steps 0.001 milli ohm
  • Accuracy 0.05% for premium dials
Cropico RBB Decade Resistance Box

Cropico RBB Decade Resistance Box

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A versatile range of resistance Decade Resistance Boxes, available in 5 & 6 decades. Both high accuracy and a wide range, 0.001 ohm to 11 mega ohm, are combined in a rugged case.

The switches used are gold plated to ensure a low contact resistance and negligible thermal E.M.F.

Some models employ the Waidner Wolf technique to eliminate the errors that may be caused by the variations in switch contact resistance. These models are particularly suited to applications such as Pt100 simulation where resolutions as low as 0.001 ohm (» 0.0025°C) are required.

Cropico RBB Decade Resistance Box

to Request a Quote
RBB5 RBB6 Decade Accuracy Current Max mA
                10 x 0.001Ω  ± 2% 2000
            10 x 0.01Ω  ± 1% 2000
        10 x 0.1Ω  ± 0.5% 2000
    10 x 1Ω  ± 0.2% 600
10 x 10Ω  ± 0.05% 200
10 x 100Ω  ± 0.05% 60
    10 x 1kΩ  ± 0.05% 20
        10 x 10kΩ  ± 0.05% 6
            10 x 100kΩ  ± 0.1% 2
                10 x 1MΩ  ± 0.1% 0.3


Model No. Decades Total Resistance Resolution Suitable for Pt100 Simulation Resolution °C when Simulating Pt100  Residual Resistance Ω
RBB5-B 5  1,112.1Ω 0.01  0.025
RBB5-C 5  11,111Ω  0.1 0.012Ω
RBB5-D 5 111,110Ω 1 0.012Ω
RBB5-E 5 1.1111MΩ  10 0.012Ω
RBB5-F 5 11,111Ω 100 0.012Ω
RBB6-B 6 1,112.11Ω 0.001  0.0025
RBB6-C 6 11,112.1Ω 0.01 0.025
RBB6-D 6 111,111Ω 0.1 0.013Ω
RBB6-E 6 1.11111MΩ 1 0.013Ω
RBB6-F 6 11.1111MΩ 10 0.013Ω
Calibration   Weight
Calibration certificates including UKAS traceable are available on request  

RBB5 - 0.5kg

RBB6 - 0.6kg

Switches   Size

Contact material gold plated brass

Contact resistance = 5 Mega ohm

Insulation Resistance (all paths = 10 giga ohm)

Proof voltage 1kV

  350mm x 100mm x 80mm (W H D) approx (all models)

Temperature Co-efficient:
±3ppm / +20°C to +85°C ±5ppm maximum over –55°C to + 125°C 0.1, 0.01, and 0.001 dials 10ppm/°C

Full Load Stability:
±35ppm/10,000 hours ±50ppm/26,000 hours

No Load Stability:
±25ppm/10,000 hours ±35ppm/26,000 hours

Over full temperature range:
-50°C to +125°C

Power Rating:
0.33 watt (+85°C) 0.25 watt (+110°C)

Maximum Continuous Working Voltage:
70Vdc / 33vrms

Essentially non-measurable <1.5 mV/°C

Thermal E.M.F:
<0.4mV/°C typical

Moulded epoxy

Exclusive ‘air cushioned’ technique provides virtually stressless elements for improved performance. Non inductively wound. Direction of winding reversed at half turns point



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