What is Gauss Meter : Working & Its Applications

Carl Friederich Gauss is a great mathematician and also a pioneer in the study of magnetic fields. He invented one of the first measuring devices namely the magnetometer or Gauss meter in 1833 that is capable of measuring the direction & strength of a magnetic field. He also invented a system of units to determine magnetism. So, the current unit of magnetic induction or magnetic flux density in the CGS system is called the gauss whereas, in the SI measurement system, the magnetic flux basic unit is the tesla (1 tesla = 10,000 Gauss). This article discusses an overview of a gauss meter and its working with applications.

What is Gauss Meter?

The measurement instruments like a Gauss meter are mainly used to compute the magnetization of a magnetic material’s like a ferromagnet  or otherwise it can be stated as it is used to measure the direction & strength of the magnetic field at a specific point in space. A gauss meter includes a gauss probe, the meter & a cable to fix them. This meter simply works because of the Hall Effect. This meter is also used to measure small magnetic fields.

Gauss Meter
Gauss Meter

Hall Effect is a method where a transverse electric field can be developed within a solid material when the material is located in a magnetic field that carries an electric current which is perpendicular to the magnetic field. Then the voltage can be measured at the right angle to the existing path. So this method of measuring voltage because of magnetic effect is called the Hall Effect.

How Does Gauss Meter Work?

The most essential part of a gauss meter is the Hall probe. This probe is flat and measures transverse magnetic fields. Some probes are cylindrical or axial that are simply used to calculate parallel fields toward the probe. For instance; a magnetic field in a solenoid

Both types of probes can be used for measuring the magnetic fields, however transverse or flat probes are important for measuring magnetic fields within open spaces like small gaps in magnets otherwise for ferromagnetic objects or simple magnets. Generally, probes are delicate, particularly when they are used to gauge small magnetic fields & they are resistant with brass material for safety from rugged surroundings.

The gauss meter utilizes the probe to transmit a test current using the conductor and because of the Hall Effect, the voltage can be produced, which is recorded by the meter. When the voltage changes, then the meter freezes the voltage readings at a particular value and records them once the highest value of voltage is detected.

Gauss Meter Vs Magnetometer

The difference between gauss meter and magnetometer includes the following.

Gauss Meter


A gauss meter is a measuring device, used to measure the strength/ intensity of a magnetic field to discover its direction. A magnetometer is used to estimate a particular magnetic field value within a specified or given area.
This meter includes a Hall probe/gauss sensor, the meter & a connecting cable wire. Magnetometer includes the magnetometer housing, electrostatic shield &  the assembly of a magnetometer.
The gauss meter is a precise measuring device due to 1% of accuracy. These meters are extremely accurate.
This meter displays the measurements of an electromagnetic wave in Gauss.


Magnetometer detects EMFs (electromagnetic fields (EMFs) & simply displays measurement results within mG (milliGauss) or µT (microTesla).
The weight of the gaussmeter is approximately1kg. The weight of the magnetometer is approximately7.7 kg with terminations.


Circuit Diagram for Gauss Meter

The circuit diagram for the gauss meter is shown below. This gauss meter circuit is very simple and low-cost to design. We know that the gauss meter is mainly used for measuring the magnetic field’s strength.
The designing of this circuit can be done by using a 9V battery, an IC LM1117-5.0 (voltage regulator), a toggle switch like S1, an SS49E Hall effect sensor like IC2, a two-pin connector like CON1 to connect a DVM (digital voltmeter), or DMM (digital multimeter).

Gauss Meter Circuit Diagram
Gauss Meter Circuit Diagram

SS49E Hall Effect Sensor

The pinout of the SS49E Hall Effect sensor is shown below which includes three pins.

  • Pin1 (Vdd): This is a power supply pin.
  • Pin2 (GND): This is a GND pin of the IC.
  • Pin3 (Output): This is an out pin of the IC.

Electrical Characteristics

The electrical characteristics of the SS49E Hall Effect sensor are shown below.

  • The operating voltage (Vcc) ranges from 3.0v to 6.5V.
  • The package of IC is TO-92.
  • Response time is 3 µsec.
  • The current supply (Icc) ranges from 4.2 to 8.0mA.
  • Output current (Iout) is 1.0 to 1.5mA.
  • Output voltage (Min) is 0.86V.
  • Output voltage (Max) is 4.21V.
  • Quiescent o/p voltage is 2.25 to 2.75V.
  • Sensitivity (ΔVout) is 1.6 to 2.0 mV/G.

Circuit Working

Once the switch ‘S1’ is closed then the voltage at the ‘TP1’ test point is 5volts whereas the voltage at TP2 mainly depends on the magnet position with respect to the IC2 sensor. Here to check the meter readings whether stable or not over the battery life, a fixed voltage regulator is employed that provides a stable DC power source toward the sensor.

Now the magnet’s field strength can be measured by keeping the magnet away from the Hall Effect sensor and placing the digital voltmeter probes across two-pin connector ‘CON1’.   After that, move the magnet in the direction of the hall sensor and measure the voltage.

So you can notice two o/p voltages in the digital voltmeter based on the magnet position with respect to the Hall Effect sensor. If the voltage reading is at its maximum within the digital voltmeter, then the hall sensor is facing in the South Pole direction of the magnet. Similarly, if the voltage reading in DVM is minimum then, the sensor faces in the direction of the north pole of a magnet.

The strength of the magnetic field can be measured in Gauss by using the following relationship:

Magnetic Flux Density (B) = 1000*(V1-V2)/k Gauss

Where the o/p voltage ‘V1’ without magnet close to the hall sensor

The output voltage ‘V2’ with the magnet close to the hall sensor.

‘ k’ is the sensor’s typical sensitivity (mV/G).

Gauss Meter Example Problem:

Note that, ‘V1’ must be approximately 2.5V. If the hall sensor is placed near to the South Pole of the magnet then ‘V2’ will increase & reduce if it is placed close to the North Pole.

For instance, if you measured 2.50 Vdc in DVM for ‘V1’ and 1.35 Vdc for ‘V2’, then,

B = 1000*(V1-V2)/k Gauss

B = 1000*(2.5–1.35)/1.80 => 638 Gauss

Here, the result is positive, so it specifies that the magnet is in the North Pole direction.

Similarly, if you measured 2.50 Vdc for ‘V1’ and 3.50 Vdc for ‘V2’ then

B = 1000*(2.50 – 3.50)/1.80 => –555 Gauss

Here, the result is negative which means the magnetic is in the South Pole direction.

Gauss Meter Design with Hall Effect Sensor & Arduino

This project is used to design a Gauss meter with an Arduino Uno R3 & KY-003 Hall Effect sensor. This meter is used to measure the strength as well as the polarity of a magnetic field. The required components to make this project mainly include;

Arduino UNO R3 board, PC, 16X2 LCD, KY-003 Hall effect sensor, speaker magnet, breadboard, jumper wires, Type-B USB, potentiometer, etc. The three essential components of this project mainly include KY-003 Hall Magnetic Sensor, 16x 2 LCD & Arduino UNO R3.

The Hall Magnetic Sensor like KY-003 mainly includes a sensitive 3144EUA-S Hall-effect switch used for the operation of high-temperature, a resistor with 680Ω & an LED. This sensor includes three pins GND, VCC & digital output. The first pin is the GND pin which is connected to the GND pin of Arduino, the middle pin of this sensor is VCC (+5V), connected to 3.3V/5V of the Arduino,& the final pin ‘S’ is the data pin, connected to any of the Digital input pins of the Arduino board.

This sensor is one kind of switch that controls the existence of a magnetic field. By locating the magnet close to the hall sensor the LED will turn on automatically. The magnetic field polarity can control the switching action.

The LCD display including an I2C module can be connected to the Arduino board by using two Data cables. This module includes an inbuilt potentiometer that is used for the adjustment of contrast. This LCD includes 16 columns & 2 rows.

The Arduino UNO R3includes 14 digital I/O pins where 6 pins are PWM outputs, 6 pins are analog inputs, a USB connection, a 16 MHz quartz crystal, an ICSP header, a power jack, 32k Flash Memory & a reset button.

The 16×2 LCD display includes four pins VCC, GND, SCL & SDA. The connections of these pins can be done like this. The VCC pin of an LCD is connected to 5V of Arduino, the GND pin of LCD is connected to the GND pin of Arduino, The SCL pin of LCD is connected to the A4 pin of Arduino, and the SDA pin of LCD is connected to A5 pin of Arduino.

Connect all these components within one circuit using a potentiometer for calibration of the magnetometer. Once the connections are made, download the libraries for Arduino and LCD.

Gauss Meter using Arduino & Hall Effect Sensor Module
Gauss Meter using Arduino & Hall Effect Sensor Module

Project Code

#include <Wire.h&gt> // Librries need to add at the primary line of the code.//
#include <LiquidCrystal_I2C.h> //include the LCD type for 16X2 LCD through 0x27 i2c backpack address //
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
#define sensorPin 10 //Define the output pin of the components sensor pin to arduino//
#define calibrationPin 1
float sensorRead;
float calibrationRead;
float sensorPinVoltage;
float calibrationPinVoltage;
float gauss;
void setup() { // At this function write the command that begins serial connection. Call this method runs once after the Arduino board is powered up//
lcd.begin(16, 2);
lcd.print(“Hall effect”);
delay (500);
void loop() {
sensorRead = analogRead(sensorPin);
calibrationRead = analogRead(calibrationPin);
if (sensorRead >= 1020 || sensorRead <= 3){
lcd.print (“INTENSIT”),
lcd.print(“Y ERROR!”);
sensorPinVoltage = ((5 * sensorRead) / 1023);
calibrationPinVoltage = ((5 * calibrationRead) / 1023);
gauss = ((1000 * (calibrationPinVoltage – sensorPinVoltage)) / 1.3);
lcd.print (gauss, DEC),

Finally, we can observe the current gauss meter value with the KY-003 Hall Effect sensor & LCD.


The advantages of the Gauss meter include the following.

  • These meters are portable.
  • Convenient to operate.
  • Sensitive.


The disadvantages of the Gauss meter include the following.

  • Expensive devices.
  • The measurement value of the Gaussian meter changes based on the manufacturer.
  • Measurement is not accurate.


The applications of the Gauss meter include the following.

  • A Gauss Meter is used to measure the small magnetic field’s direction & intensity.
  • These meters are used for the measurement of non-destructive magnetic fields in loudspeakers, in AC motors, DC motors, magnetic circuits otherwise different components like relays, coils, or magnetic switches.
  • These devices are also used for determining whether any inert or active electromagnetic fields are influencing the exact electronic devices working at the location of their installation.
  • These are reliable measuring devices used for the existing magnetic field measurement.

Is a Gauss Meter the Same as an EMF Meter?

An EMF meter is used to measure AC electromagnetic fields (EMFs), which are generally produced from man-made sources like electrical wiring whereas gauss meters measure DC fields, which naturally occur in the geomagnetic fields of Earth & are generated from other types of sources where DC is present.

What is a Gauss Reading?

The reading which is used in applications where the field strength works as the main parameter like a sensor application is known as gauss reading.

What is a High Gauss Reading?

Gauss signifies the number of magnetic field lines for each square centimeter produced by a magnet. When the value is higher, then more magnetism lines are emitted through the magnet and when such a high value is read it is  known as high gauss reading.

What Does a Gauss Meter Detect?

A gauss meter detects either dynamic (AC) EMFs, static (DC) permanent magnetic fields otherwise both. This meter displays the measurements of electromagnetic waves in different units like G (Gauss), mG (milliGauss), mT (milliTesla) otherwise µT (microTesla).

Thus, this is all about an overview of a Gauss meter and its working with applications. This is a scientific measuring instrument, that typically measures a magnetic field otherwise flux density within gauss or G (metric units) otherwise in tesla orT (the IS unit or international system unit). Here is a question for you, what is the Tesla meter?

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