Conversion of Galvanometer into Voltmeter

• Important to convert galvanometer into voltmeter practical for Intermediate students.
• APPARATUS: A moving coil (Weston type) galvanometer, voltmeter of 0 - 3 volts range, High resistance box, fractional resistance box, battery (of 2 or 3 cells), two plug keys, rheostat, connecting wires and sand papers.
• Important conversion of galvanometer into voltmeter practical for Intermediate students.
• PROCEDURE: I drew circuit diagram and made tight connections according to diagram. I connected H.R.B, battery, key K, and galvanometer in series which forms a loop. Then I connected F.R.B along with K₂ in parallel to galvanometer. I closed K₁ and opened K₂. I plug out suitable resistance from H.R.B and obtained even number deflection on galvanometer. Now I also closed K, and observed that deflection on galvanometer becomes zero. Then I plug out shunt resistance S from F.R.B which makes deflection on galvanometer half. 1 calculated resistance of galvanometer by formula G= RS/R-S
• Important how to convert galvanometer into voltmeter class 12 for Intermediate students.
• I took two more observations by changing values of R and S by same method. I calculated mean value of resistance of galvanometer.
• Important conversion of galvanometer into voltmeter pdf for Intermediate students.
• Then I noted the emf of cell using a voltmeter and calculated current passing through the galvanometer with resistance R by formula I=E/R+G
• Important conversion of galvanometer into voltmeter formula for Intermediate students.
• I calculated the current required for full scale deflection by
• Where n is the total number of divisions in galvanometer scale. For conversion of galvanometer into a voltmeter up to 3 volt, I calculated the suitable high resistance required to convert galvanometer using formula.
• Important conversion of galvanometer into voltmeter class 12 for Intermediate students.
• Rh = 3.0 Ig Then I connected a H.R.B, voltmeter and galvanometer according to circuit diagram (C)
• and noted the deflection on galvanometer and reading on voltmeter. The potential difference shown by converted galvanometer is equal to the reading on standard voltmeter. I took three number of readings by varying the rheostat.
• Important conversion of galvanometer into voltmeter class 12 practical for Intermediate students.
• Diagram
• Observations: 
• Current for full scale defection (using Ohm's law)
• E.M.F. of the battery (or cell) with a voltmeter = E = 1.3 volts
• Total number of divisions on the galvanometer scale = n = 30 divs. From observation No. 01 (take 1 or 2 or 3), geniopsy inst wit betelupies.
• Important conversion of galvanometer into voltmeter practical observations for Intermediate students.
• Resistance R 4000 Ohms.
• Deflection = 0= 30 divs.
• Current passing through galvanometer = bak R+G (Ohm's law) QU
• Shimanovlarens of bougies
• Current for full scale deflection (30 div) = 1 = -x n Hence: 1=- Ex30 1.3 x30 = (R+G)0 (4000+123.2)30 -3 A=0.315x10 A = 0.315 mA
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• Range of voltmeter = 3V R₁=--Galib
• High resistance which is to be connected with the galvanometer = V
• Rh = 3.0 0.315x10-3 -123.2mun  R= 9524 Ω
• Checking the accuracy of the converted galvanometer
• Calculations 
• RESULT: In order to convert the galvanometer into voltmeter reading up to 3.0 volts, a high resistance R = 9524 ohms must be connected in series with the galvanometer.
• PRECAUTIONS :All the connections should be neat and tight.
• The positive marked terminal of standard voltmeter should go to the positive terminal of the battery.
• Both voltmeter i.e standard voltmeter and converted galvanometer should be connected parallel with the resistance box.
• Suitable resistance should be taken out from the resistance box to produce large deflection in both voltmeters.
• The rheostat used as potential divider should not have low resistance.
• (Note: If the difference between the readings of converted galvanometer and voltmeter is large we should adjust the value of external resistance in the resistance box placed in series with the galvanometer unless the readings coincide.)