Clamp meter is the abbreviation of clamp ammeter. It is a portable measuring instrument that can directly measure the AC current of the circuit without disconnecting the circuit. It is called a clamp ammeter because of its shape with a movable opening in the shape of a clamp. Common clamp meters do not have the ability to measure AC and DC voltages of 1kV or above. It is recommended not to measure parameters higher than this voltage to avoid personal electric shock.