All test and measurement instruments, regardless of their brand and manufacturing quality, need periodic calibration to ensure accuracy within proscribed limits. High voltage insulation testers are no exception and are customarily calibrated using highly accurate and stable resistors.
The A 1740 Calibration box 5 kV uses not one, but 4 such resistors (different measuring ranges) for calibrating selected high voltage insulation testers. It can also be used for simulating the resistance of wires, cables and insulators, provided the connected voltage doesn’t exceed 5 kV.
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