Amplifier Gain and Decibels

Gain is the ratio of output to input; decibels express ratios on a logarithmic scale.

Easy

$A_v = \frac{V_{out}}{V_{in}} \qquad A_v(\text{dB}) = 20\log_{10}A_v \qquad A_p(\text{dB}) = 10\log_{10}\frac{P_{out}}{P_{in}}$

Gains of cascaded stages multiply — or simply add in dB. dBm is power relative to 1 mW; dBV is voltage relative to 1 V.

Spotted a mistake or want to add detail? Suggest an improvement — Content Contributors' edits are reviewed by editors before they go live.

Discussion (0)