To convert the given galvanometer (of known resistance and figure of merit) into an ammeter of desired range and to verify the same. Since Galvanometer is a very sensitive instrument therefore it can't measure heavy currents. In order to convert a Galvanometer into an Ammeter, a very low resistance known as "shunt" resistance is connected in parallel to Galvanometer. Value of shunt is so adjusted that most of the current passes through the shunt. A "moving coil" galvanometer shows a deflection proportional to current flowing through its coil due to very small voltages placed across its.
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When you are designing the ammeter, you need to select a value of Rs depending upon the max current you intend to measure. For ex - an ammeter which can measure current up to 1 A will use a larger value of Rs as compared to an ammeter which galvanometer to ammeter measure a current up to A.
Suppose you wish to use it to measure much larger currents, say 1 A, at the end of its scale. galvanometer to ammeter
The rest of that large current 1 A minus 0. If, when adjusting the shunt, you let the whole big current go through the galvanometer, even momentarily, you might damage the galvanometer galvanometer to ammeter.
The coil resistance of a galvanometer is typically a few Ohms to a few hundred Ohms. Typical full-scale For the sake of galvanometer to ammeter explanation, let us assume a very sensitive galvanometer with Ohm coil resistance, and microAmperes current for full-scale deflection.
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Thus, by Ohms Law, the full-scale deflection will require 10 mV across the terminals. To create an ammeter with a maximum current rating of 1 Ampere, this current must generate 10 mV across galvanometer to ammeter "load resistor" or "shunt resistor".
When you convert a galvanometer into an ammeter, it is like cheating galvanometer to ammeter customer: P Suppose your customer comes and tells. I want it to read from 0 to units of current. You connect a shunt resistance a resistance in parallel with the galv.