Voltage gain - simplified formula (for equal impedances)


The power gain can be calculated using voltage instead of power using Joule’s first law to calculate a voltage gain. In many cases, the input and output impedances are equal.

This simplified formula, the 20 log rule, is used to calculate a voltage gain in decibels and is equivalent to a power gain only if the impedances at input and output are equal.

Related formulas


gaindBVoltage gain (dB) (dimensionless)
VoutOutput voltage (dimensionless)
VinInput voltage (dimensionless)