Open-loop gain
= Open-loop gain
{title2=$A(s)$}
{wiki}
The <open-loop gain> of an <operational amplifier> is the ratio of its output voltage to its differential input voltage before an external <feedback control> connection is applied. A common small-signal model is $A(s)=A_0/(1+s/\omega_a)$, with a large direct-current gain $A_0$ and a dominant pole at $-\omega_a$. Above $\omega_a$ its magnitude falls approximately inversely with <angular frequency>.