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Eddy Currents
Any conductor which is moving so as to cut through magnetic field lines or is surrounded by a changing magnetic field, has an emf induced in it.  
   
The induced emf can cause a current to flow.  
   
The name "eddy current" is used to refer to currents induced to flow in:  
1. the iron cores of transformers, motors, generators etc
2. the aluminium formers (supports) on which galvanometer coils are wound.
 
   
Eddy Currents in Iron Cores  
Eddy currents covert electrical energy into thermal energy.  
This represents wasted energy and so it reduces the efficiency of the machine.  
   
To reduce the loss of energy due to eddy currents the cores are "laminated" (made of thin sheets of iron separated by a layer of insulator).  
   
Supports for Galvanometer Coils  
The current induced in the support opposes the motion of the coil (another example of Lenz's law)  
This has the effect of damping the motion of the coil. That is, it allows the coil to move (of course!) but prevents if from oscillating.  
A meter in which the coil is wound on a plastic (insulating) support oscillates for a long time before finally giving reading.  
   
Some galvanometers are made with coils on insulating supports in order to measure charge (rather than current).  
If the charge flows through the coil in a very short time (a few milliseconds or less) then the initial amplitude of the resulting oscillation of the coil can be shown to be directly proportional to the quantity of charge that flowed through it.
Such a galvanometer is called a ballistic galvanometer.  
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