Clamp meters are highly efficient at safely and speedily measuring current, without interrupting the current flow or using test leads. The clamps measure current such as AC current, AC and DC voltage, resistance, and continuity. Some models can also measure DC current, capacitance, temperature, and frequency...
As a measurement principle, clamp meters detect the magnetic field emitted by current flowing in a wire in order to measure the current value. Unlike instruments like multimeters, this design has the advantage of being able to measure current without requiring that the circuit under measurement be cut.