- cross-posted to:
- science_memes@mander.xyz
- cross-posted to:
- science_memes@mander.xyz
cross-posted from: https://lemmy.world/post/27589038
You must log in or # to comment.
Welcome to the field of engineering! Your first lesson will be; “Tolerances and you”!
Where are the spherical cows?
No no no no, I think you got that wrong. Chickens are spherical, cows on the other hand are cuboid. And humans are cylindrical.
Chickens, cows, and humans all are toroids. True story.
would be a great band name
I kinda wonder if there’s a specific reason for that number other than just being an ass.
2pi
would start with 6.28
He’s bad at math/estimating
Tau
wau
This is EXACTLY how it went for me when I moved from a Physics to an Electronics Engineering degree at University.
Also, the trying to understand how the various circuits worked from the point of view of “electrons moving” was a hard to overcome early tendency (even simple things like LC circuits, for example, are only really understandable as ressonant stable states and for complex circuits you really have to go higher levels than “electrons” to be able to understand then in any reasonable amount of time).
On the upside when we got to things like how tunnel effect diodes worked, the whole thing was just obvious because of having had an introduction to Quantum Mechanics in the Physics degree. Also the general stuff about how semiconductor junctions work is a lot more easy to get if you come from Physics.
(In summary: Physics really helps in understanding HOW the various components in Electronics work, but doesn’t at all help in understanding how to use them to assemble a complex structure to achieve a given objective. Curiously this also applies to Mathematics and Software Development)
well there’s certainly none in the chip aisle
Watching people repair old electronics on Youtube has opened my eyes to the realities of real-world electrical engineering. In short: it’s all about tolerances.
A power supply may have a nominal voltage of 5V, but anything from 4.8 to 5.2 is a-okay. Why? Because your TTL components downstream of that can tolerate that. Components that do 5V logic can define logic zero as anything between 0 and 0.8 volts, and logic one as low as 2 volts. That’s important since the whole voltage rail can fluctuate a lot when devices use more power, or draw power simultaneously. While you can slap capacitors all over the place to smooth that out, there’s still peaks and dips over time.
Meanwhile, some assembly lines have figured out how to aggressively cost-reduce goods by removing whole components from some circuits. Just watch some Big Clive videos. Here, the tendency is to lean heavily into those tolerances and just run parts hot, under/over powered, or just completely outside the published spec because the real-deal can take it (for a while). After all, everything is a resistor if you give it enough voltage, an inductor if the wire’s long enough, a capacitor if the board layout is a mess, and a heatsink if it’s touching the case.
The way I got 100 in a lab once (electrical engineering) was by not using inductances in a frequency filter because their +/- is shit.
You’re getting a 10 ohm resistor and liking it.
More seriously, if you order it from an Electronics supplier, you can get a 6.2 Ohm resistor with a mere 1% tolerance (in some cases, even 0.5%).
That said an EE, except in very specific cases such as reference resistors, would generally use a 10 or 5 Ohm one with 10% tolerance for any circuit that was supposed to be mass produced since it’s far cheaper and much more easy to source in the size you require.
Electronics engineering is a bit beyond my scope; as an electronics hobbyist or field repairman you’re gonna get the closest I have in my kit at the time, I’ll probably get within an order of magnitude of the spec unless it’s somehow very damn critical or the schematic calls for one of the oddly common oddly specific values like 220 ohm.
Well, just think “How would I do this cheaply and get away with it” for a good enough “Engineering” approach for this case.
The really expert “Engineering” stuff related to things like maintenability, reliability, robustness and so on (which I myself am not qualified to talk about, as even though I have an EE degree, that’s not actually the domain of Engineering I ended up working in so I haven’t accumulated the professional experience that teaches one to take such higher level considerations into one’s designs), isn’t, IMHO, really necessary to understand to explain why those designing circuits commercially would chose the commonly available and cheaper components if they can.
There is though. Iirc up to 15 digit subohm precision trimmed resistors are a thing just an uncommon and extremely expensive thing.
just get a variable resistance, aka a potentiometer, and have fun adjusting it to get that value.
Astrophysicists would be happy with a 1 ohm resistor.
You should see their simplified periodic table.
