How does a clamp meter work?

How does a clamp meter work?It is often very difficult to measure the current directly, since the value of the current is too large to apply it directly to the meter circuit, or simply because it is unacceptable to break the circuit.Clamp current sensors are designed to enhance the measuring possibilities of digital multimeters, power meters, oscilloscopes, portable oscilloscopes, recorders or self-recorders, and other various devices.A current sensor for measuring the parameters of alternating current can be regarded as a kind of a simple current transformer.On a closed magnetic circuit in the form of clamp that is closed to the conductor, there is the secondary coil, through which passes an electric current, induced by a current in the conductor under measurement.The conductor, where user holds the measurements, is one turn of primary winding.The current sensor, closed around the conductor, generates an output current, the value of which is directly proportional to the current in the conductor. Given a ratio of transformation, the value of current in the wire, around which the sensor is closed, can be easily determined.If the measurable value is too small, several loops of the conductor can be closed by the clamp, in order to enable the operation of the sensor, or to increase the measurement accuracy. The current value is determined by the ratio of the sensor indications to the number of turns of the conductor, covered by the clamp (sensor indications must be divided by the number of turns, closed by the clamp).Unlike traditional electromagnetic alternating current converters, the measurement of the parameters of alternating and direct currents is often performed by measuring the intensity of the magnetic field, created by the conductor in a semiconductor crystal in accordance with Hall effect.When the excitation current in the Hall-effect device is maintained to be constant, the intensity of the magnetic field is directly proportional to the current in the conductor under measurement. Thus, the output voltage corresponds to a given current.Such a circuit has two important advantages for the measurement of current:The first is that since the Hall voltage is independent of changes in the magnetic field direction. It depends only on the value of its intensity, thus, this device can be used to measure the direct current.The second advantage is that when the voltage of the magnetic field changes due to the changes in the current in the conductor, the ...