Brace

Brace (English: Amplifier) is an electronics component that is used to strengthen the power (or energy in general).

In the field of audio, amplifier will amplify the sound signal (which has been expressed in the form of electric current) on the input it into electric current is stronger at the output
The amount of strengthening is often known by the term gain. Value of the gain is expressed as a function of frequency is called the transfer function
So the gain is the result of the power output (Pout) and power at the input is (Pin) in the form of a function of frequency. The size of the gain, (G) is usually the Decibel (dB). In formula form this is expressed as follows:
G (dB) = 10log (Pout / Pin)). Pout is the Power or power at the output, and Pin is the input power on it