Problem 57-1    Source:   Problem elaborated by the author of the site.

At the input of a circuit, a sinusoidal signal of 1.0 Vrms was applied and at the output of the circuit a signal with an intensity of 2.0 Vrms was measured. Calculate, in dB, whether there was gain or loss of the signal.

Solution of the Problem 57-1   

By the statement of the problem, we must calculate the gain or loss of voltage and, it is known that  V_o = 2.0 Vrms  and    V_i = 1.0 Vrms. The equation that allows the calculation of the voltage gain is given by:

Then, making the numerical substitution and calculating:

Therefore, it is concluded that there is a gain of voltage (note the positive signal of the result) of the order of + 6 dB in relation to the input signal.