Experiment of Magnetic Induction

Experimental set-up

 

Objective:

The objective of this experiment is to measure the induction voltage as a function of the current in the field coil at a constant frequency and calculate the magnetic constant µₒ.

Principles:

There are two coils use in this experiment long coil and short coil.  A magnetic field of frequency and varying strength is produced in a long coil. The voltages induced across thin coil which are pushed into the long coil are measured depending on the frequency of the current in the field coil and the strength of its magnetic field as well as the number of turns and the diameter of the induction coil.

Apparatus:

• Field coil / Primary coil / Long coil, Length 'L' = 750mm,  Number of turns 'N' = 485 turns
• Induction coil / Secondary coil / Short coil, n = 150 turns,  diameter 'd' = 25mm
• Function generator
• Digital/Analogue multimeters (DMM)

Setup:

The experimental set-up is as shown in Fig. 1. The coil current and the induction voltage are measured with the digital multimeters. The effect of frequency should be studied between 1 kHz and 12 kHz, since below 0.5 kHz the coil practically represents a short circuit and above 12 kHz the accuracy of the measuring instruments is not guaranteed.

Procedure:

1. Connect first DMM in series of Function Generator and Primary/Long Coil, then set DMM knob to A.C Ampere.
2. Connect second DMM in parallel of Secondary/Short coil, and then set DMM knob to A.C Voltage.
3. Set Function Generator frequency and amplitude.
4. Fix frequency on function generator and vary value of voltage or amplitude on function generator.
5. Draw data on table.
6. Then find the value of slope using this formula,  Slope= ΔVs/ΔIp.
7. Take values of Vs from Second DMM and value of Ip from First DMM. 

S.No                    Vp                Ip(mA)                    Vs(mV)