Electrical measurement assigns a value and unit to a quantity such as voltage, current, resistance, power, energy, frequency or phase. The result depends on the instrument, connection method, range, bandwidth, sampling process and operating conditions. A measurement is complete only when its uncertainty and relevant conditions are understood.
Choose an instrument with a suitable input rating, resolution, accuracy, bandwidth and safety category. Account for loading, lead resistance, probe capacitance, noise, temperature, calibration status and repeatability. Traceability requires a documented chain of calibrations to a stated reference, with each calibration contributing to the uncertainty.
