Apparatus:

Two solenoids, Constant current supply, Four probe, Digital gauss meter, Hall effect apparatus (which consist of Constant Current Generator (CCG), digital milli voltmeter and Hall probe).

Simulator controls

Combo box

Select procedure: This is used to select the part of the experiment to perform.

1. Magnetic field Vs Current.
2. Hall effect setup.

Select Material: This slider activate only if Hall Effect setup is selected. And this is used to select the material for finding Hall coefficient and carrier concentration.

Button

Insert Probe/ Remove Probe: This button used to insert/remove the probe in between the solenoid.
Show Voltage/ Current: This will activate only if Hall Effect setup selected and it used to display the Hall voltage/ current in the digital meter.
Reset: This button is used to repeat the experiment.

Slider

Current: This slider used to vary the current flowing through the Solenoid.
Hall Current: This slider used to change the hall current
Thickness: This slider used to change the thickness of the material selected.

Procedure for doing the simulation:

Part A: Measurement of Magnetic Field

In this part of the experiment, you will determine the magnetic field generated by the electromagnet. These magnetic field values will be used later to calculate the Hall coefficient.

Step 1: Select the Magnetic Field Measurement Procedure

1. Open the Hall Effect simulator.
2. From the Select Procedure drop-down menu, select Magnetic Field Vs Current.

Step 2: Insert the Magnetic Probe

1. Click the Insert Probe button.
2. Place the probe between the two pole pieces of the electromagnet by clicking on the wooden stand provided in the simulator.
3. Ensure that the probe is positioned correctly before taking any measurements.

Step 3: Measure the Magnetic Field

1. Move the Current slider to its minimum value.
2. Observe the magnetic field displayed on the Gauss Meter.
3. Record the current and the corresponding magnetic field value.

Step 4: Repeat the Measurements

1. Increase the current gradually using the Current slider.
2. Wait until the Gauss meter reading becomes stable.
3. Record the corresponding magnetic field.
4. Repeat the procedure for at least five different current values.

Observation Table – Magnetic Field Measurement

Trial	Current (A)	Magnetic Field (Tesla)
1
2
3
4
5

Note: Use these magnetic field values in Part B.

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Part B: Determination of Hall Coefficient and Carrier Concentration

Step 1: Select the Hall Effect Setup

1. Select Hall Effect Setup from the Select Procedure menu.

Step 2: Insert the Hall Probe

1. Click Insert Hall Probe.
2. Place the Hall probe between the poles of the electromagnet.

Step 3: Select the Sample Material

1. Select the required semiconductor material.
2. Keep the material unchanged throughout the experiment.

Step 4: Set the Sample Thickness

1. Adjust the Thickness slider.
2. Keep the thickness constant.

Step 5: Set the Hall Current

1. Adjust the Hall Current slider.
2. Keep the Hall current constant.

Step 6: Apply the Magnetic Field

1. Adjust the electromagnet current until the required magnetic field (from Part A) is obtained.

Step 7: Measure the Hall Voltage

1. Click Show Voltage.
2. Record the Hall voltage.

Step 8: Repeat the Measurements

1. Repeat the procedure for each magnetic field value while keeping the material, thickness, and Hall current constant.

Step 9: Record the Results

Record the displayed Hall Coefficient and Carrier Concentration.

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Calculations

The Hall coefficient is calculated using

$$R_H=\frac{V_Ht}{IB}$$

where

• R_H = Hall coefficient (m³/C)
• V_H = Hall voltage (V)
• t = Sample thickness (m)
• I = Hall current (A)
• B = Magnetic field (T)

Carrier concentration is calculated using

$$n=\frac{1}{R_He}$$

where

• n = Carrier concentration (m⁻³)
• e = 1.602 × 10⁻¹⁹ C

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Observation Table – Hall Effect

Trial	Magnetic Field (T)	Thickness (mm)	Hall Current (mA)	Hall Voltage (mV)	Hall Coefficient (m³/C)	Carrier Concentration (m⁻³)
1
2
3
4
5

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Procedure for doing real lab

• Connect “Constant current source” to the solenoids.
• Four probe is connected to the Gauss meter and placed at the middle of the two solenoids.
• Switch ON the Gauss meter and Constant current source.
• Vary the current through the solenoid from 1A to 5A with the interval of 0.5A, and note the corresponding Gauss meter readings.
• Switch OFF the Gauss meter and constant current source and turn the knob of constant current source towards minimum current.
• Fix the Hall probe on a wooden stand. Connect green wires to Constant Current Generator and connect red wires to milli voltmeter in the Hall Effect apparatus.
• Replace the Four probe with Hall probe and place the sample material at the middle of the two solenoids.
• Switch ON the constant current source and CCG.
• Carefully increase the current I from CCG and measure the corresponding Hall voltage $V_H$ . Repeat this step for different magnetic field **B**.
• Thickness **t** of the sample is measured using screw gauge.
• Hence calculate the Hall coefficient $R_H$ using the equation 5.
• Then calculate the carrier concentration **n** using equation 6.

Precautions

1. Insert the probe correctly before taking measurements.
2. Position the probe at the center of the electromagnet poles.
3. Keep the material, thickness, and Hall current constant.
4. Wait for stable readings before recording observations.
5. Use the magnetic field values measured in Part A.
6. Record all values with proper units.
7. Reset the simulator before performing another experiment.

Result

Hall coefficient of the material = .........................

Carrier concentration of the material = ......................... m^-3