Terminology » Measurements » Magnetic Field Sensor Basics and Types

Magnetic Field Sensor Basics and Types

magnetic field sensor magnetometer gaussmeter measurement

This page provides a fundamental overview of magnetic field sensors and discusses various types. Popular magnetic field sensors include:

  • Induction Coil
  • FluxGate
  • SQUID (Superconducting Quantum Interference Device)
  • Hall Effect
  • Magnetoresistance
  • Proton Precession
  • Optically Pumped

The primary purpose of a magnetic field sensor is to measure the strength of a magnetic field. This strength can be expressed in units of Amperes per meter (A/m), Tesla (T), or Gauss (G). The selection of an appropriate sensor depends on the required magnetic field strength measurement range. These sensors are integral components in the manufacturing of magnetic field meters, also known as EMF (electromagnetic field) meters.

Magnetic Field Sensor Types

Magnetic field sensors are generally categorized into two main types: vector and scalar.

Vector type magnetic sensors are further divided into those used for low-field measurements and those used for high-field measurements. Instruments employing low-field sensors are commonly referred to as magnetometers, which are designed to measure fields less than 1 milliTesla (mT). On the other hand, instruments using high-field sensors are known as gaussmeters and are capable of measuring fields greater than 1 mT.

Vector Type Magnetic Field Sensors (Magnetometers)

The following are vector type magnetic field sensors typically used in magnetometers:

  • Search Coil
  • Fluxgate
  • SQUID
  • Magneto-resistive
  • Fiber Optic

Scalar Type Magnetic Field Sensors (Magnetometers)

Scalar type magnetic field sensors also find use in magnetometers. Examples include:

  • Proton Precession
  • Optically Pumped

Magnetic Field Sensors Used in Gaussmeters

The following types of magnetic field sensors are commonly found in gaussmeters:

  • Hall Effect
  • Magneto-resistive
  • Magneto-diode
  • Magneto-transistor

These classifications are based on factors such as field strength range, resolution, and bandwidth. These characteristics guide the selection of appropriate sensors for specific field strength measurement instruments.

Magnetic Field Sensor Specifications

Sensor TypeRange (mT)Resolution (nT)Bandwidth (Hz)Description
Induction Coil10−1010^{-10} to 10Variable10−110^{-1} to 10610^6Cannot be used to measure static fields.
FluxGate10−410^{-4} to 0.50.1DC to 2×1032 \times 10^3Used in general-purpose vector type magnetometers.
SQUID10−910^{-9} to 0.110−410^{-4}DC to 5Magnetometer with higher sensitivity.
Hall Effect0.1 to 3×1043 \times 10^4100DC to 10810^8Best suited for fields greater than 1 Tesla.
Magnetoresistance10−310^{-3} to 510DC to 10710^7Good for mid-range applications.
Proton Precession0.02 to 0.10.05DC to 2Scalar magnetometer for general-purpose use.
Optically Pumped0.01 to 0.10.005DC to 5Scalar magnetometer for high-resolution needs.