[en] The critical current (I_c) of a superconductor can be measured using a variety of measurement systems and techniques. The measurement system should be chosen based upon several considerations including accuracy, the number of samples to be measured, and measurement environment. The system may vary in complexity from a simple analog recorder that monitors the voltage-current characteristic, to a sophisticated computerized data acquisition system that monitors several different experimental parameters. Various measurement techniques are available for measuring I_c including the dc, pulse, and ac methods. Each technique, along with its advantages and disadvantages, is discussed