ESI (Electro-Scientific Inds.) SR1050-1M Resistance Transfer Standard 1 Meg/step

Description

ESI (Electro-Scientific Industries) SR1050-1M Resistance Transfer Standard 1 Megohm/step
Description
Based on a unique method for establishing known ratios, the ESI SR1050 standard utilizes a transfer technique that consists of switching resistance sections in parallel, series or series-parallel sections. An outstanding design feature is a structure in which the only insulation leakage paths (other than those within each resistance section) are from the external terminals to ground. This eliminates insulation leakage errors in the transfer of calibration from one resistance level to another using three-terminal measurement techniques. A specially designed lever switch provides a convenient means of switching into parallel and series parallel configuration without introducing insulation leakage errors. External shorting or paralleling bars are not necessary. Each resistance section consists of precision wire-wound resistors connected in series. The reduced heat concentration of the series connection improves the thermal characteristics of a resistance element with an already low temperature coefficient
Advantages of Transfer Standards
In order to perform calibrations with a high degree of accuracy, reference standards must be employed at every range or decade of the measuring or calibration instrumentation. Clearly, this can be difficult and costly since these standards must be highly stable and their precise values must be known with a high degree of certainty and sufficient resolution. To minimize the cost and difficulty, more practical means of performing such calibrations is to use transfer standards.
ESI SR1050 Transfer Standards Basic Specifications
Transfer Accuracy
Limited only by short-term repeatability of resistance values. Typical repeatability 2 ppm
Long-Term Accuracy
50 ppm of nominal value
Temperature Coefficient
5 ppm/°C, matched within 5 ppm/°C
Power Coefficient
0.05 ppm/mW per resistor
Maximum Power Rating
1W/step or 5W distributed over 10 steps, or maximum voltage of 2.5 kV where this value does not result in power excess of 1W per resistor
Breakdown Voltage
5000 V peak between active terminals and case
Leakage Resistance
Greater than 10 TΩ from terminals to case
Operator manual is available http://www.nousnexus.com/Manuals/ESI_SR1050_im.pdf.
Condition: Resistors are good but some of the switches need to be mechanically adjusted or repaired. Selling as-is for parts or repair.
Dimensions: 35.6 cm W x 16.5 cm H x 10.2 cm D (14” x 6.5” x 4”); Weight: 5 kg (11 lbs)