design iteration
Nobody throws a perfect pot on the first spin of the wheel. You shape it, see where it is lopsided, push it back, and shape again — each pass a little closer to round. Design iteration is that same loop for circuits: build, measure, learn what is wrong, change it, and go around again. The first version is never the last. Iteration is not a sign that you failed at planning; it is the planned, normal way that a fuzzy idea becomes a trustworthy product.
Each loop is build, measure, diagnose, change. You prototype, you test against the spec, and where it falls short you ask why — was the calculation wrong, the part out of spec, the layout noisy, the spec itself unrealistic? Then you make one or a few deliberate changes and go round again. The skill is changing little and learning much: alter one thing at a time so the next measurement actually tells you what that change did, keep notes on each revision, and resist the urge to rewire ten things at once and then have no idea which one helped.
The honest mindset of mastery lives here. Early iterations are cheap and meant to fail informatively — you learn most from the version that does not work. Each loop should converge, getting measurably closer to the spec, not just shuffle problems around; if it is not converging, the topology or the spec may be wrong, and no amount of tweaking will save it. Know when to stop, too: chasing the last one percent past what the spec actually needs is a way to burn schedule for nothing. Good enough, proven by measurement, beats perfect in your head.
Rev A reads 3 percent high. You change only the gain resistor and measure again: now 0.5 percent high. Because you changed one thing, you know the resistor was the cause. Rev B is within spec, so you stop — chasing the last 0.5 percent would cost a week for accuracy nobody asked for.
Change one thing at a time so each measurement tells you what that change did.
If iterations are not converging — each fix breeds a new problem — stop tweaking. The fault is usually in the topology or the spec, and more revisions will only burn time.