Advertisements
Advertisements
Question
A galvanometer coil has a resistance of 12 Ω and the metre shows full scale deflection for a current of 3 mA. How will you convert the metre into a voltmeter of range 0 to 18 V?
Solution
Resistance of the galvanometer coil, G = 12 Ω
Current for which there is full scale deflection, Ig = 3 mA = 3 × 10−3 A
Range of the voltmeter is 0, which needs to be converted to 18 V.
∴ V = 18 V
Let a resistor of resistance R be connected in series with the galvanometer to convert it into a voltmeter. This resistance is given as:
R = `"V"/"I"_"g" - "G"`
= `18/(3 xx 10^-3) - 12`
= 6000 − 12
= 5988 Ω
Hence, a resistor of resistance 5988 Ω is to be connected in series with the galvanometer.
APPEARS IN
RELATED QUESTIONS
The combined resistance of a galvanometer of resistance 500Ω and its shunt is 21Ω. Calculate the value of shunt.
Explain how moving coil galvanometer is converted into a voltmeter. Derive the necessary formula.
A moving coil galvanometer has a resistance of 25Ω and gives a full scale deflection for a current of 10mA. How will you convert it into a voltmeter having range 0 - 100 V?
State the principle of the working of a moving coil galvanometer, giving its labeled diagram ?
A moving coil galvanometer has a coil of resistance 59 Ω. It shows a full-scale deflection for a current of 50 mA. How will you convert it to an ammeter having a range of 0 to 3A?
A galvanometer coil has a resistance of 15 Ω and the metre shows full scale deflection for a current of 4 mA. How will you convert the metre into an ammeter of range 0 to 6 A?
A galvanometer of resistance 100 Ω gives a full-scale deflection for a current of 10−5 A. To convert it into an ammeter capable of measuring up to 1 A we should connect a resistance of ______.
A galvanometer having a coil resistance of 60 Ω shows full-scale deflection when a current of 1.0 amp passes through it. It can be converted into an ammeter to read currents up to 5.0 amp by:
How is current sensitivity increased?
