| Description |
Tight
tolerance versions of the IET labs HARS-X Description Series for
applications requiring a cost effective high performance resistance
decade standard suitable for laboratory and field calibrations. |
|
Resistor Type |
Resistance
wire for 0.1 steps and under; hermetically sealed, wirewound non-inductive
resistors for 1 Ω steps and over. |
| Range |
10
mΩ up to 12.1 MΩ in 1 to 10 decades. |
| Resolution |
1
mΩ discrete steps; 20 µΩ continuous resolution
rheostat; 1Ω mΩ full scale, option RH. |
| Initial
Accuracy (absolute) |
<±(25
ppm + 0.5 mΩ); at 23°C, no zero subtraction required,
<±(20 ppm + 0.5 mΩ); at 23°C, no zero subtraction
required, 4-terminal, “true-ohm” measurement, SI traceable. |
| Initial
Adjustment Accuracy |
±1
ppm for 10 kΩ steps; ±1.5 ppm for 100 kΩ steps;
±3 ppm for 1 MΩ steps.
(For increased accuracy of the 1 Ω to 1 MΩ decades,
individual resistors for these decades are trimmable.) |
| Temperature
Coefficient |
<±20
ppm/°C for 10 Ω steps and under;
<±5 ppm/°C for 100 Ω steps and over.
<± 50 µO/°C for wiring and switch resistance. |
| Stability |
<±(20
ppm + 0. 5 mΩ)/year; <±5 ppm/year, typical. |
| Minimum
Resistance |
10
mΩ ± 0.5 mΩ; limited by the lowest settable position,
“1”, of the 10 mΩ/step decade. |
| Power
Maximum |
0.5
W per step up to 3 W total or 2 A max. |
| Calibration
Conditions |
Four-terminal
measurement, low power, at 23°C; 30% to 60% RH. |
| Switch
Type |
11
positions, "0"-"10", multiple solid silver alloy
contacts,
with short term contact resistance repeatability of <100 µΩ. |
| Breakdown
Voltage |
1500
V peak to case |
| Power
Coefficient |
<±1000
ppm/W for 0.1 Ω steps and under
<±400 ppm/W for 1 Ω steps
<±300 ppm/W for 10 Ω steps
<±100 pm/W for 100 Ω steps and over.
<+50 µΩ/W for wiring and switch resistance. |
| Terminals |
Low
thermal emf beryllium copper binding posts with standard 3/4 inch
spacing plus shield terminal; connection from the rear of the instrument
is available as option RO. |