How does amplifier work?

Replies

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  Kaustubh Katdare

  senthilr88

  i was very much interested in electronics. i need to know how the transistor amplifier works. in no one book i was satisfied. plz help me

  Look here, my friend: #-Link-Snipped-#
  
  If you ask specific questions about amplifiers, we might be able to help. Don't lose interest in electronics.
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  vasanthmbs

  which amplifier either by transistor or op-amp.........
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  Jivesh

  The only problem in many books is that they don't tell the general idea of an amplifier. An amplifier is a device in which one of the output parametres(either voltage or current) is controlled by any one of the input parametres. The relation should be proportional, with the constant of proportionality represents the intrinsic gain of the amplifier. Now, we need devices which can implement such a control. In a BJT transistor, we have the output current controlled by the input current. Similarly, in MOSFET the output current is controlled by the input voltage. These devices are fabricated in such a way in which we can control the output parametres in the specified manner, as required in a transistor.
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  Sukesh

  The main use of transistors is amplification. But how it accomplishes it is interesting.Just as you can drive a heavy vehicle using the a small force at the accelerator pedal(the actual power is given by the fuel,accelerator only guides its rate) transistors are controlled via their base region.A very small voltage at the base can make the collector voltage to vary similar to it. But the collector region has a different power source.So the collector output is larger.This takes place in the active operating mode of the transistor.For more clear idea refer the Electronics text by Bhargava.