Re: what is the difference between a A B A,B C amplifier

Good Question!
The answer is not simple.  The difference between Class A, Class AB, 
Class B....amplifiers is in whether current flows in the amplifier or 
not, and how efficient the amplifier is, that is, how much of the 
*supply* power of the amplifier can be actually delivered to the load.

Class A amplifiers have current continuously flowing in amplifier 
regardless of whether or not power is delivered to the load.
Class AB amplifiers also have current continuously flowing in the 
amplifier, but not as much as Class A.
Class B amplifiers do not have current flowing in the amplifier unless 
there is some power being delivered to the load.  As such, they are more 
efficient than Class A or AB.
Class C amplifiers do not have current flowing in the amp unless *a lot* 
of power is being delivered to the load.  Therefore, they are more 
efficient than Class B amplifiers.
There are also Class D, Class E, and Class T amplifiers...more efficient 
still.

The power you can get from any of these amplifiers is theoretically 
unlimited:  if you build a big enough amp in any class, you can get the 
power you want out of them.

Don't use any of these amplifiers to drive a Tesla coil:  IT'S NOT SAFE!!!

Hope this helps!