What is dB in Electronics Engineering?

Answer 1

Deci-bels (dB) are a logarithmic measure of system/network amplification or gain (G). The logarithms are taken to the base 10 and multiplied by 20:

dB = 20logG (where G is the gain of the system)

To give an example of what this means:

G = 0.01, so dB gain = 20log0.01 = 20 * -2 = -40dB

G = 0.1, so dB gain = 20log0.1 = 20 * -1 = -20dB

G = 1, so dB gain = 20log1 = 20 * 0 = 0dB

G = 10, so dB gain = 20log10 = 20 * 1 = 20dB

G = 100, so dB gain = 20log100 = 20 * 2 = 40dB

G = 10000, so dB gain = 20log10000 = 20 * 4 = 80dB

There are other uses for dB in electronics, where logarithms are useful they are preferred. The reasons logs can be useful is because the natural log of an exponential curve is a straight line, allowing for easier ways of understanding the behaviour of a system.