12 Difference Between Voltage And Power Amplifier

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Voltage Amplifier

A voltage amplifier is an amplifier that amplifies given voltage for a larger voltage output. It is characterized by a high input impedance and low output impedance. This is useful for reading and adapting small signals such as boosting an audio signal before sending it on its way to speakers.

 The voltage amplifier is a form of the common emitter amplifier which relies on the transistor, the amplification of voltage is dependent on the ratio of resistors on the collector and emitter of this transistor.

What You Need To Know About Voltage Amplifier

  1. The voltage amplifier amplifies the voltage or increases the voltage level of a signal.
  2. The voltage amplifier can work with low magnitude signal.
  3. In voltage amplifier, the amplitude of input A.C signal is small.
  4. The transistor used in the voltage amplifier has a thin base because it does not handle large current.
  5. The output impedance of the voltage amplifier is very high, about 12 kilo-ohm.
  6. The collector current of the voltage amplifier is very low up to 1 mA.
  7. The transistor used can dissipate less heat produced during its operation.
  8. The physical size of transistor used is usually small and is known as low or medium power transistor.
  9. RC coupling is used in voltage amplifier.
  10. In power amplifier, the collector load has low resistance, typically 5Ω to 20Ω.
  11. Voltage amplifier is used for small signal voltage.
  12. The current gain of the voltage amplifier is very low.

Power Amplifier

Power amplifier as the name suggests is an amplifier that makes a given input current higher. It is characterized by a low input impedance and high output impedance. It is usually used in the last output stages of a circuit. Examples include: audio power amplifiers, servo motor controllers, push-pull amplifiers and RF power amplifiers.

What You Need To Know About Voltage Amplifier

  1. The power amplifier amplifies the power of a signal.
  2. The input signal of the power amplifier must have a high magnitude.
  3. In power amplifier the amplitude of input A.C signal is large.
  4. The transistor used in the power amplifier has a thick base because it handles the very large current.
  5. The output impedance of the power amplifier is very low, up to 200 ohm, so that it can deliver a high current.
  6. The collector current of the power amplifier is high greater than 100 mA.
  7. The transistor used can dissipate more heat produced as compared to voltage amplifier during its operation.
  8. The physical size of transistor used is usually large and is known as power transistor.
  9. Transformer coupling is used in power amplifier.
  10. In voltage amplifier, the collector load has high resistance, typically 4Ω to 10kΩ.
  11. Power amplifier is used for high voltage signals.
  12. The current gain of the power amplifier is very high.

Difference Between Voltage And Power Amplifier In Tabular Form

BASIS OF COMPARISON VOLTAGE POWER AMPLIFIER
Use The voltage amplifier amplifies the voltage or increases the voltage level of a signal.   The power amplifier amplifies the power of a signal.  
Functionality The voltage amplifier can work with low magnitude signal.   The voltage amplifier can work with low magnitude signal.  
Amplitude Of AC Signal In voltage amplifier, the amplitude of input A.C signal is small.   In power amplifier the amplitude of input A.C signal is large.  
Transistor The transistor used in the voltage amplifier has a thin base because it does not handle large current.   The transistor used in the power amplifier has a thick base because it handles the very large current.  
Output Impedance The output impedance of the voltage amplifier is very high, about 12 kilo-ohm.   The output impedance of the power amplifier is very low, up to 200 ohm, so that it can deliver a high current.  
Collector Current The collector current of the voltage amplifier is very low up to 1 mA.   The collector current of the power amplifier is high greater than 100 mA.  
Transistor Heat Dissipation The transistor used can dissipate less heat produced during its operation.   The transistor used can dissipate more heat produced as compared to voltage amplifier during its operation.  
Size Of Transistor The physical size of transistor used is usually small and is known as low or medium power transistor.   The physical size of transistor used is usually large and is known as power transistor.  
Collector Load In power amplifier, the collector load has low resistance, typically 5Ω to 20Ω.   In voltage amplifier, the collector load has high resistance, typically 4Ω to 10kΩ.  
Coupling RC coupling is used in voltage amplifier.   Transformer coupling is used in power amplifier.  
Application Voltage amplifier is used for small signal voltage.   Power amplifier is used for high voltage signals.  
Current Gain The current gain of the power amplifier is very high.   The current gain of the power amplifier is very high.  

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