Measurement of Dielectric Constant in Liquid (Resonance Method)

 Measurement of Dielectric Constant in Liquid (Resonance Method)

SCOPE OF LEARNING:

To calculate Dielectric constant of solids. The instrument consists of a high frequency R.F. Oscillator of tuneable frequency with outer gang condenser, optimum tunning is indicated on meter. The change in meter reading after placing Dielectric material between parallel plates can be detected and difference can be noted, workable on 220VAC, 50 Hz.

TECHNICAL SPECIFICATIONS:

• F. Generator (Range: 9-10MHz approx.).
• mMicro ammeter (Range : 0-50
• Potentiometer for Sensitivity selection.
• Test Capacitor For Solid (Metal Aluminium Sheets With Variable Air Gap)
• Test Capacitor For Liquid (Round Metal Aluminium Sheets With Fixed Air Gap)
• Variable Gang Capacitor.
• Sockets for test capacitor and variable capacitor brought out at front panel.
• One Solid Bakelite plate to be insert in rap of test capacitor

 Supply Include

• Dielectric Constant Apparatus.
• Variable Gang Condenser.
• Test Capacitor For Solid (Metal Aluminium Sheets With Variable Air Gap)
• Test Capacitor For Liquid (Round Metal Aluminium Sheets With Fixed Air Gap)
• Three type of Bakelite sheets for Dielectric material.
• Two sets of Leads

 FORMULA USED:-

                Dielectric constant,is given by k=1+

C₀=capacity of test capacitor without dielectric(it is given)

C₁=capacity of variable air capacitor for maximum deflection in micrometer when test capacitor                                          

is  without dielectric.

C₂= capacity of variable air capacitor for maximum deflection in micrometer when test

capacitor is filled with dielectric.

Procedure :-

1. Connect R.F.Oscillator (Dielectric Constant Apparatus) terminals to given variable capacitor’s. Set the sensitivity of the meter at 0.5 by vary the sensitivity potentiometer knob.
2. Switch on the instrument and note down the value of C’ by just connecting the standard capacitor and tuned to resonance
3. Now connect another capacitor (test capacitor) to second terminals.
4. The frequency of the oscillator is fixed and is kept constant throughout the experiment.
5. Keep test capacitor without dielectric and vary capacity of variable air capacitor so that deflection in micrometer is maximum. This value of Air Capacitor is C₁.
6. Now fill test capacitor with dielectric. Again vari the capacity of variable air capacitor so that deflection in microammeter  is maximum . Let this value of variable air capacitor be C2
7. Repeat the procedure of different dielectric& space between plate .Value of the dielectric constant all to be noted from the appendix given at the last sheets of manual.

For measuring dielectric of solids, connect capacitor plates in parallel with gang capacitor.set meter for maximum resonance by variying the variable capacitor. Put dielectric plates in between the gap of capacitor .Resonence change retune the gange c

Precautions:-

1. Test capacitor’s plate must be tight when filled with dielectic material.

Observations:-

Capacity of variable air capacitor C₀=……………pf.

Capacity of variable air capacitor C₁=……………pf.

Capacity of variable air capacitor C₂=…………..pf.

Value of c0 is given different gap

https://www.youtube.com/watch?v=mVWSn04gmIk&t=43s