A current standard consisting of a current source, shunt resistor, and voltmeter is classified as what?

The classification of a current standard that includes a current source, shunt resistor, and voltmeter aligns with the definition of a derived standard. A derived standard is created from a primary standard and is calibrated against it to ensure accuracy. In this case, the components work together to measure and verify current levels based on established relationships, such as Ohm's law, where voltage, current, and resistance are interconnected.

A derived standard varies somewhat from a primary standard, which is a measurement standard that is directly realized and has absolute accuracy under defined conditions. The reference standard serves as a benchmark utilized for comparisons but does not derive its values from another standard in the way a derived standard does. Thus, the combination of these elements provides a means to achieve practical measurements and calibrations that operate on the principles established by the primary standards.

Understanding these definitions is essential, as they help calibration technicians identify the appropriate standards for measuring electrical currents in various applications effectively.