Wall-plug efficiency
= Wall-plug efficiency
{title2=$\eta_{\rm WPE}=P_{\rm opt}/P_{\rm elec}$}
The emitted optical <power> divided by electrical input <power>. For the bare-device calculation in <light-emitting diode efficiency>, $P_{\rm elec}=IV_f$; a complete lamp also consumes <power> in its driver. <Luminous efficacy>, measured in lumens per watt, additionally weights the <spectrum> by human visual sensitivity and is a different quantity.