The term amplification means the process of increasing the power, voltage, or current by the application of electronic components.
The term amplifier is an electronic circuit that has the capability to amplify power, voltage, or current.
The amplification phenomenon is linked to active devices. One of the major practical benefits of active devices is their amplifying ability. Whether the device in question is voltage-controlled or current-controlled, the amount of power required for the controlling signal is typically far less than the amount of power available in the controlled current. In other words, an active device doesn’t just allow electricity to control electricity; it allows a small amount of electricity to control a large amount of electricity.
Amplifiers are able to take in small-power signals and output signals of much greater power. The key to understanding how amplifiers can exist without violating the Law of Conservation of Energy lies in the behavior of active devices.
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