Large AC/DC current measurement using Hall effect sensor
Some applications require us to measure and display large current like motors, amplifiers, transmission lines or current collectors without actually disturbing the actual setup. In this post I will describe how to make large current measurement using non-contact method.
We will use hall effect based current sensor for this purpose.
Hall Effect
When a current-carrying conductor is placed into a magnetic field, a voltage will be generated perpendicular to both the current and the field. This principle is known as the Hall effect.
The Hall voltage is proportional to the amount of current and magnetic field strength.
The main advantage of this sensor is its form factor which makes it easier to put on a PCB. Other advantage being current measurement range- which is upto hundreds of ampere.
Thus by reading analog signal at AI pin, we can measure current through a target.
Some applications require us to measure and display large current like motors, amplifiers, transmission lines or current collectors without actually disturbing the actual setup. In this post I will describe how to make large current measurement using non-contact method.
We will use hall effect based current sensor for this purpose.
Hall Effect
When a current-carrying conductor is placed into a magnetic field, a voltage will be generated perpendicular to both the current and the field. This principle is known as the Hall effect.
Vh = Kh* BI/t
Kh is Hall coefficient, B is magnetic field strength, I is the current through the conductor, t is the thickness across which voltage is generated.
The current carrying wire passes through the aperture of the sensor. A hall element is fitted inside the core of these sensors. The magnetic flux around the wire interferes with the Hall element and generates a voltage signal. The scheme of measurement is as shown:
The Hall voltage is a low-level signal on the order of 30 microvolts per unit gauss magnetic field. This low-level output is prone to noise and requires an amplifier to amplify it to suitable level..
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| Signal details of CSLA2CD sensor |
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| CSLA2CD Hall effect current sensor |
The main advantage of this sensor is its form factor which makes it easier to put on a PCB. Other advantage being current measurement range- which is upto hundreds of ampere.
Thus by reading analog signal at AI pin, we can measure current through a target.
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