What are these bits at the end?

[drdn0]

Why do you care?

If you build millions, the price per part approaches zero. SMD resistors especially.

If you build just one, the price per part is often much-much less than the value of the brain-pain to figure which parts are not needed.

Yes in DIY you do not charge yourself for thinking but it still has value. Hard to evaluate, but perhaps similar to the time we have spent discussing in this thread. We have *about* 1,000 words invested so far. I don't have a rate-chart for thinking+writing, but writing alone goes around 1,000 word per hour. Working alone is less time writing but more time thinking. So say we have 'thought' for about 1 hour. What are wages today? McD's offers $15/hr here for flipping. Targeting thinking should be worth more. Can you think-away $20 of parts in an hour? Not in a one-off DIY economy: the whole guts may not be $20. (Yes, the assembly of pointless parts is another work-cost and easier to balance against thinking-cost.)

Unnecessary parts reduction IS vital in medium production. Cars and planes, semi-fancy TV sets. These products can support hard-thinking designers but not radical production machinery.

(FWIW, my 2023 Toyota engine probably has more parts than my 1967 Mercury engine. 4-valve, variable cams, variable oil pump, two fuel injection systems.....)

(FWIW, Intel no longer counts how many transistors are in a CPU, so probably not how many are useless.)

Why do we use hundreds of different values resistors when we could just keep adding in 470R's until we get close enough to what we need? Why do we use op-amps when we could build it discrete?

Obviously this is hyperbole, but the same principles apply. If we can make something that sounds incredible with 10 components or 100 components, unless you're a glutten for punishment or love shilling for THE TOAN, you're going to choose 10 every single time regardless of how little the difference is in cost.

There's no reason not to apply this same principle to anything we build, especially if we have any sort of sense of curiosity.