when using decibels for voltage measurements explain the sig

Solution

dB is an abbreviation for \"decibel\", generally used to compare voltage values especially with circuits that exhibit
hign input impedance and let little current flow. Usually, the voltage based dB equals to 20 log Vout / Vin.

0dB means the reference level to which all +dB and dB figures refer.

3dB is commonly used for limits of an amplifier\'s bandwidth which can be defined as the difference between the lower and upper half power points.

This occurs either the output power has fallen to half the maximum or mid band power or
when the voltage at output drops by 1/2 or 0.707 of the maximum output voltage which is approxmately -3.0103dB.

The half power point is approximately 3 dB because 10 log 2 = 3.010 ~~ 3

The half power point means the frequency at which the output power has dropped to half of its mid-band value(usually known as cutoff frequency).

Generally, a lowpass or highpass mplifier will have only one half power point(cutoff frequency) where as bandpass amplifier will have 2 half power points.

6dB means where the voltage dampens to half of its amplitude where as 6dB refers double the voltage amplitude.