The working principle of the current probe when testing DC and low-frequency AC: When the current clamp is closed and a current-carrying conductor is surrounded in the center, a corresponding magnetic field will appear. These magnetic fields deflect electrons within the Hall sensor, creating an electromotive force at the output of the Hall sensor. The current probe generates a reverse (compensating) current based on this electromotive force and sends it to the coil of the current probe to make the magnetic field in the current clamp zero to prevent saturation. The current probe measures the actual current value based on the reverse current. With this method, large currents, including mixed AC and DC currents, can be measured very linearly.