what is torque converter?

Answer 1

A torque converter is required in an automatic transmission in place of a clutch.
Its basically a fluid coupling between the engine & transmission.
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Answer 2

actually this is a very good question to ask. A torque converter is a couple between the engine and transmission. it is responsible for converting the power from the engine to useable force for the transmission. basically its like this
A torque converter is modified form of a hydrodynamic fluid coupling, and like the fluid coupling, is used to transfer rotating power from a prime mover, such as an internal combustion engine or electric motor, to a rotating driven load. As with the fluid coupling, the torque converter takes the place of a mechanical clutch. Unlike a fluid coupling, however, a torque converter is able to multiply torque when there is a substantial difference between input and output rotational speed, thus providing the equivalent of a reduction gear. the torque converter can have several differnt stall speeds depending on applications. they will differ between a stock built engine to a drag racing engine to help aid in the performance aspect and driveablility of the vehicle. I hope this helps a little.

Answer 3

http://auto.howstuffworks.com/torque-converter.htm

That should answer all your questions about it.

Answer 4

automatic transmission's verison on the clutch

Answer 5

Check the link below, it should fill you in!