Compare auto transformer with two winding transformer.

Compare auto transformer with two winding transformer.
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3 Answers

Answer :

Two winding transformer Auto-transformer
There are two windings in this transformer for primary side and secondary side. There is only one winding in this transformer for primary side and secondary side.
Both windings are electrically isolated. Winding is not electrical isolated.
If number of turns on secondary side is more than primary side it acts as step up transformer. If the winding for output have more number of turns than the input it acts as step up transformer.
There are two separate windings for primary and secondary. 
Only one winding, part of the winding is common for primary and secondary.
No movable contact between primary and secondary
Movable contact exist
Electrical isolation between primary and secondary windings.
Electrical connection between primary and secondary. 
Comparatively more losses
Comparatively lower losses.
Efficiency is less as compared to autotransformer.
Efficiency is more as compared to two winding transformer.
Copper required is more.
Copper required is less, thus copper is saved. 
Core type or shell type core construction
Spiral core construction
Most of the general purpose transformers where fixed voltage is required. 
Special applications where variable voltage is required.
Cost is more
Cost is less 
Poor voltage regulation
Better voltage regulation





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edited

Answer :

Points
Two winding transformer
Autotransformer
Symbol
image
image
Number of windings
It has two windings
It has one winding 
Copper saving
Copper saving is less
Copper saving takes more as compared to two winding
Size
Size is large 
Size is small 
cost
Cost is high
Cost is low
Losses in winding
More losses takes place
Less losses takes place 
Efficiency
Efficiency is low
Efficiency is high
Regulation
Regulation is poor
Regulation is better
Electrical isolation
Electrical isolation is present in between primary and secondary winding
There is no electrical isolation
Movable contact 
Movable contact is not present
Movable contact is present 
Application
Mains transformer, power supply, welding, isolation transformer
Variac, starting of ac motors, dimmerstat. 
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Answer :

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Autotransformer and Two winding transformer

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