Principle of Clamp Ammeter and Current Clamp for Measuring Current
In daily work, for most engineers, multimeter is selected to measure electrical signals such as voltage, small current, resistance, etc. When large current needs to be tested, clamp Ammeter is generally preferred. Clamp watches are as important a tool in the minds of engineers as a multimeter.
Principle of clamp Ammeter
There are two types of clamp watches: single AC clamp watches and AC DC clamp watches, with different principles.
Single AC clamp meter: The clamp head adopts an electromagnetic current transformer. Through a coil with a certain turn ratio, alternating current can generate electromagnetic induction in the clamp head coil, obtaining a current proportional to alternating current. Then, through conversion, the electrical signal is converted into a digital signal.
AC/DC clamp meter: The clamp head adopts Hall active current clamp. Active components can not only sense the electromagnetic field of alternating current, but also convert the magnetic field signal into an electrical signal, outputting a voltage signal proportional to the measured current. By relying on Hall elements to measure and amplify, the DC signal can be tested.
Testing high current: current clamp+multimeter
As is well known, a multimeter can only measure small currents (usually within 10A, 20A can last for several seconds), and it is necessary to disconnect the tested line and then connect the multimeter in series to the circuit. There is no clamp meter to measure current, which is convenient and efficient. Many industrial sites use a combination of current clamp and multimeter to test high currents, maximizing the value of the multimeter.
When using a single AC clamp meter, an AC DC clamp meter, and a multimeter in combination, there are differences in operation
Precautions for using a combination of a single AC clamp meter and a multimeter: Since the output signal of a single AC clamp meter is generally a signal conversion between mA and A, it is necessary to set the multimeter to the milliampere mA position.
Precautions for the combination of AC/DC clamp meter and multimeter: The output signal of the AC/DC clamp meter is generally converted between mV and A, so it is necessary to set the multimeter to the mV position.
