Gain

Gain ( engl. gain) is the magnification of a variable physical output over an input variable for a unique linear connection as possible. This can be primarily mechanical quantities, sizes or electric light. Preferably, the input and output size are similar. An amplifier to increase the deliverable capacity is possible, to which energy has to be supplied.

The term gain is equal for both variables (eg DC voltage with the operational amplifier ) as well as for exchange sizes used (eg with regard to the amplitude of a sinusoidal oscillation). The gain is dependent on properties of the input signal in general. Is particularly the function of the frequency of importance for the technical application.

For quantitative information using the gain as the ratio of output to input; he can be a complex number:

If <1, so if there is a slowdown, they are better on the damping factor. Of these two sizes are used, respectively one that is greater than one in the amount, which the amount has a positive log.

Often a gain level is specified as a logarithmic size. In similar sizes, from which the power depends quadratically, eg electrical voltages, currents or sound pressures, the amount of gain using the logarithm to the auxiliary unit Bel ( unit symbol B) is formed or after taking the natural logarithm of the auxiliary unit Napier ( unit symbol Np). Is example for rms values ​​of the voltage