A galvanometer having 30 divisions has current sensitivity of 20uA/division. It has a resistance of 25ohm . How will you convert it into ammeter measuring upto 1A . How will you now convert this ammeter into voltmeter reading upto 1V?
Answers
Answer:
what is galvanometer ?
A galvanometer is an electrochemical measuring device for electric current. Early galvanometer were not calibrated, but improved versions called ammeter were calibrated and could measure current flow accurately
its unit is radian/ampere
Explanation:
given:- galvanometer = 30 divisions
sensitivity 20uA/div
to find :-ammeter into voltmeter
The full scale deflection current
ig=30×(20×10−6)=6×10^−4A
If S is the required value of the shunt connected in parallel with the galvanometer, then
ig=Si/S+G⇒6×10^−4
=S/S+25×l
ig=SS+Gi⇒6×10-4=SS+25×l
After calculating
S=1509994Ω−0.01150ΩS=1509994Ω-0.01150Ω
The resistance of the ammeter
RA=SGS+G=0.0150×250.0150+25
=0.0150ΩRA=SGS+G=0.0150×250.0150+25=0.0150Ω
To convert this ammeter into the voltmeter, we can use
V=ig (RA+R0)
Here V=1V,ig=1AV=1V,ig=1A
∴1=1(0.0150+R0)
∴1=1(0.0150+R0) or
R0=0.985ohm
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