Magnetic Field Sensor basics

This page covers Magnetic Field Sensor basics and mention Magnetic Field Sensor types. Induction Coil,FluxGate,SQUID,Hall Effect,Magnetoresistance,Proton Precession and Optically pumped are popular magnetic field sensors. The page provides links to other sensors used for various applications.

The basic ourpose of magnetic field sensor is to measure magnetic field strength. It can be measured in units of A/m or Tesla or Gauss.

Based on the magnetic field strength measurement need appropriate sensor is choosen. These sensors are used in the manufacturing of magnetic field meters or EMF meters.

Magnetic Field Sensor types

Magnetic field sensors are categorized into vector and scalar types. The vector type of magnetic sensors are further divided into low field measurement sensors and high field measurement sensors.

The instruments which employ low field sensors are known as magnetometers. These magnetometers measure fields less than 1 mT. the instruments which employ high field sensors are known as gaussmeters. The gaussmeters measure fields greater than 1 mT.

The Vector type of magnetic field sensors are as follows. These are used in magnetometers.
• Search Coil
• Fluxgate
• Magneto-resistive
• Fiber Optic

The scalar type of magnetic field sensors are as follows. These are also used in magnetometers.
• Proton Precession
• Optically Pumped

The magnetic field sensors used in gaussmeters are as follows.
• Hall Effect
• Magneto-resistive
• Magneto-diode
• Magneto-transistor

These divisions are based on field strength range, resolution and bandwidth. Based on these data, sensors are used in field strength measurement instruments.

Sensor type Range (mT) Resolution (nT) Bandwidth (Hz) Description
Induction Coil 10-10 to 106 Variable 10-1 to 106 Can not be used to measure static field type
FluxGate 10-4 to 0.5 0.1 DC to 2 x 103 used in general purpose vector type of magnetometer
SQUID 10-9 to 0.1 10-4 DC to 5 Magnetometer with higher sensitivity
Hall Effect 0.1 to 3 x 104 100 DC to 108 Best to be used for fields greater than 1 tesla
Magnetoresistance 10-3 to 5 10 DC to 107 It is good to use it for mid-range applications
Proton Precession 0.02 to 0.1 0.05 DC to 2 Scalar magnetometer for general purpose use
Optically pumped 0.01 to 0.1 0.005 DC to 5 Scalar magnetometer for high resolution need

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