I was just thinking this morning aobut decibels and how would I explain the need for them to a medicine student. Then it occured to me, well, why are we using decibels when scientific notation is capable of handling large orders of magnitude just as well?
It just doesn't represent a number... It represents the
RATIO between 2 numbers. And a dB allows you to express a value whose ratio may be small (2x for example, or very large 10,000x) in an easy, "friendly", convenient format.
(voltage gain dB for example)
2x is 6dB
100x is a 40dB increase.
1,000x is a 60dB increase.
2,000x is a 66dB increase.
10,000x is a 80dB increase.
So you need 2 values to have a RATIO, your number and a reference value. What's the reference value?
if 0.775Volts, then it's called dBu
if 1.0V then it's called dBV