Cropico RS3 Series

4 terminal construction, high stability resistance standard with wide range

- Wide range 0.0001 ohm to 1 Mega ohm
- Excellent load coefficient

Share with...

Cropico RS3

The RS3 range of resistance standards are constructed using carefully selected low temperature coefficient Manganin or Zeranin wire, depending on the value, mounted on formers which have a high mechanical stability. The wires are wound in a strain free manner and heat treated to remove any stresses. They are also artificially aged under the strictest control. The result is a standard of high quality with long term stability and permanence of calibration combined with a low temperature coefficient.

The RS3 range also offers a high current carrying capability which makes them ideal for applications where precise current needs to be measured.

RS3 Specifications

RS3 SPECIFICATIONS
Model	Value	Uncertainty of Adjustment @20°C	Uncertainty of Certification	Temp Coeff Typical 15 to 20°C	Stability Over 1 Year
RS3/0001	0.0001Ω	0.02%	±200ppm	20ppm/°C	0.0025%
RS3/001	0.001Ω	0.01%	±50ppm	25ppm/°C	0.0025%
RS3/01	0.01Ω	0.01%	±25ppm	10ppm/°C	0.001%
RS3/02	0.02Ω	0.01%	±50ppm	10ppm/°C	0.001%
RS3/05	0.05Ω	0.01%	±50ppm	10pm/°C	0.001%
RS3/0.1	0.0.1Ω	0.003%	±25ppm	10ppm/°C	0.001%
RS3/1	1Ω	0.003%	±25ppm	10ppm/°C	0.001%
RS/10	10Ω	0.003%	±25ppm	10ppm/°C	0.001%
RS3/25	25Ω	0.005%	±25ppm	10ppm/°C	0.001%
RS3/50	50Ω	0.005%	±25ppm	3ppm/°C	0.001%
RS3/100	100Ω	0.003%	±25ppm	3ppm/°C	0.001%
RS3/250	250Ω	0.005%	±25ppm	3ppm/°C	0.001%
RS3/1K	1kΩ	0.003%	±25ppm	3ppm/°C	0.001%
RS3/10K	10kΩ	0.003%	±25ppm	3ppm/°C	0.001%
RS/100K	100kΩ	0.003%	±25ppm	3ppm/°C	0.001%
RS/1M	MΩ	0.01%	±25ppm	3ppm/°C	0.002%

Model	Dissipation Max in Air Watts	Dissipation Max in Oil Watts	Max. I in Air (Amps)	Max. I in Oil (Amps
RS3/001	1	4	100	200
RS3/001	1	4	32	60
RS3/01	1	4	10	20
RS3/02	1	4	7	14
RS3/05	1	4	4.5	9
RS3/0.1	1	4	3	6
RS3/1	2	10	1.4	3
RS/10	2	10	0.44	1
RS3/25	1	10	0.2	1
RS3/50	1	10	0.1	0.3
RS3/100	1	10	0.1	0.3
RS3/250	1	10	0.1	0.1
RS3/1K	1	10	0.03	0.030
RS3/10K	1	10	0.01	0.03
RS/100K	1	1	0.003	0.003
RS/1M	1	1	0.0002	0.0002

Value in ohms	Typical time constant
1Ω	+ 0.34μH/Ω
10Ω	+ 0.18μH/Ω
100Ω	+ 0.03μH/Ω
1kΩ	+ 0.04μH/Ω
10kΩ	+ 0.6μH/Ω

The resistance standards type RS3 were primarily designed as DC standards, however values above 0.1 ohm are non inductively wound and the adjacent AC characteristics are typical

Dimensions		Top Panel
160mm high x 90mm diameter approx		Bakelite marked with the value, class designation and serial number
Mass		Case
0.9kg approx		Light alloy, black anodised to give maximum heat radiation Thermometer Tube: Slotted extending the length of the resistance element
Resistance Elemants		Label
Manganin or Zeranin depending on the value. 100 ohm, 1, 10 and 100 kilo ohm low inductance winding on brass formers with PTFE insulation. 0.1, 1 and 10 ohm bifilar winding on cylindrical brass formers with PTFE insulation. 0.01, 0.001, and 0.0001 ohm resistance material in the form of straight rods or loops supported on 12mm brass conductors		Each standard is fitted with a label that describes its characteristic and operating parameters
Terminals		Maximum Continuous Working Voltage
Potential — Copper 4mm Current — Brass		60Vdc / 30Vrms