| Voltage Amplifier | Power Amplifier |
|---|---|
| In voltage amplifier the amplitude of input A.C signal is small. | In power amplifier the amplitude of input A.C signal is large. |
| In voltage amplifier the collector current is low, about 1 mA. | In power amplifier the collector current is very high above greater than 100mA. |
| 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. |
| RC coupling is used in voltage amplifier. | In power amplifier invariably transformer coupling is used. |
| The transistor used has thin base to handle low current. | The transistor used has thick base to handle large current. |
| In voltage amplifier the A.C power output is low. | In power amplifier the A.C power output is high. |
| 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. |
| In voltage amplifier the collector load has high resistance, typically 4kΩ to 10kΩ. | In power amplifier the collector load has low resistance, typically 5Ω to 20Ω. |