Why in the world do we have to amplify the current..???

 

please also tell me whata transistor is???

 

http://en.wikipedia.org/wiki/Transistor

 

You may be able to benefit from reading the material in the AAC ebook at www.allaboutcircuits.com . For example, here is a link to the passage on bipolar junction transistors.

hgmjr

 

Why in the world do we have to amplify the current..???

The answer to this is very much application specific. Do you have an example in mind?

Dave

 

Think about your television set. The signal received by the antenna is too weak to operate the picture tube or the speakers. Both the current and the voltage must be amplified.