We must remember that a negative voltage or current gain Gv or Gi indicates that there is a 180
phase difference between the input and the output waveforms. For instance, if an amplifier
has a gain of -100 (dimensionless number), it means that the output is 180 degrees outofphase
with the input. Therefore, to avoid misinterpretation of gain or loss, we use absolute values of
power, voltage and current when these are expressed in dB.
By definition,