Transconductance
= Transconductance
{title2=$g_m=(\partial I_{\rm out}/\partial V_{\rm in})_Q$}
{wiki}
The change of output <electric current> per change of input <electric potential difference>, evaluated at an <operating point> with the other terminal conditions specified. In a <small-signal model>, $i_{\rm out}=g_m v_{\rm in}$ describes this contribution; <transconductance> has the dimensions of <electrical conductance>.