= Solution
The <open-loop gain> is large and roughly constant at low <frequency>, then falls as internal <poles> become important. A dominant-pole approximation is
$$
\boxed{A(f)\simeq\frac{A_0}{1+if/f_p}}.
$$
Above $f_p$, but before higher <poles> dominate, $|A|\propto f^{-1}$, a slope of $-20\,\mathrm{dB}$ per decade, with increasing <phase> lag. The approximate unity-gain <frequency> is $f_T=A_0f_p$. A 741-class amplifier has typical low-frequency gain about $2\times10^5$; this is the <open-loop gain>, distinct from the feedback-set signal gain. The finite-gain formula at the parent level explains why the closed-loop response eventually rolls off.<LM741 Operational Amplifier by Texas Instruments>[§6.5, p. 5, large-signal voltage-gain row]{ref}
Back to article page
