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General description of the
used ESI SR1050
for sale.
The ESI SR1050 Resistance Transfer Standard utilizes a transfer technique that consists of switching resistance sections in parallel, series, or series-parallel sections. There are no solid insulation leakage paths to ground other than at the terminal points, regardless of the configuration into which the individual resistance steps may be switched. A unique and outstanding design characteristic of the ESI SR1050 Resistance Transfer Standard obviates the need to support resistors from a common insulating sheet or from insulators mounted on a common conducting surface. Each active resistance step consists of three wire-wound elements connected in series, plus a fixed trimming element for obtaining precise final value adjustment. The reduced head concentration that results from distributing the dissipated power over three elements rather than in a single resistor improves the thermal characteristics of an already low-temperature-coefficient resistance element. The ESI SR1050 will also function as a voltage divider. In this mode, the only solid insulation leakage paths to ground are from the three terminals. These leakages will range between 10^13 and 10^16 ohms, except under the most adverse environmental conditions. Specifications. Resistance Values: 1 megohm and 10 megohms per step. Transfer Accuracy: Limited only by short-term repeatability of resistance values. Typical repeatability ±2 ppm. Calibration Accuracy: 10 ppm for 1 megohm and 15 ppm for 10 megohm steps. Initial Accuracy (including calibration accuracy allowance): ±25 ppm, matched within 10 ppm, for 1 megohm steps, ±30 ppm, matched within 10 ppm, for 10 megohm steps. Long Term Accuracy: ±50 ppm of nominal value guaranteed for 1 year, typically maintained for life of instrument. Temperature Coefficient of Resistors: ±5 ppm/°C, matched within 5 ppm/°C. Power Rating: 1 W/step, or 5W distributed over 10 steps, or maximum applied voltage of 2.5kV where this value does not result in power in excess of 1W per resistor. Breakdown Voltage: 5kV peak between active terminals and case. Leakage Resistance: Greater than 10 ^13 ohm from terminals to case.
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