16 February 2018

Compare Voltage Amplifier and Power Amplifier

Voltage amplifier

  • The function of the voltage amplifier is to raise the voltage level of the input signal. 
  • The input resistance of the transistor is low whereas the output resistance of the transistor is very high. 
  • The collector resistance should be comparatively high. 
  • The transistor is employed with thin base therefore the value of current amplification factor β is high. 
  • The first stage of the multistage amplifier should be voltage amplifier.i.e. RC coupling. 
  • Less distortion in the output signal
Power amplifier

  • The function of the power amplifier is to raise the power level of the input signal. 
  • The base of the transistor is made thicker in order to handle large current. 
  • The size of the power amplifier is made sufficiently larger in order to dissipate heat. 
  • As the base is handle large current, the value of current amplification factor β is small ( IC = β IB
  • The last stage of the multistage amplifier should be power amplifier.
  • Large distortion in the output signal
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