Yes
Comment on Virgin Physicists
CausticFlames@sopuli.xyz 3 days ago
couldnt you technically fine tune a potentiometer to be this resistance if you were precise enough?
LodeMike@lemmy.today 3 days ago
HowAbt2morrow@futurology.today 3 days ago
True. Would the effort have any beneficial application? Aside from being bad ass.
LodeMike@lemmy.today 3 days ago
No
InternetCitizen2@lemmy.world 3 days ago
Therefore we should do it anyway.
expatriado@lemmy.world 3 days ago
9 significant figures? good luck!
MelodiousFunk@slrpnk.net 3 days ago
You’ll make do with three and you’ll like it!
disguy_ovahea@lemmy.world 3 days ago
The tolerance would be greater than the difference anyway.
Croquette@sh.itjust.works 3 days ago
Don’t sneeze right next to it with that kind of precision.
takeda@lemm.ee 3 days ago
Sure, except the resistance will constantly change with time, temperature and other environmental variables.
Aceticon@lemmy.dbzer0.com 2 days ago
For starters resistance changes with temperature.
Also even in a multi-turn potentiometer, getting a precision of 1 in 10^9 would require an equal level of precision in the angle you rotate that potentiometer to (for example, a 0.1 degree error in a 10 turn potentiometer - which I believe is more turns than anything that actually can be bought - translates into a 1 in 36,000 error in resistance, so about 3000 larger than 10^9) even if you had a perfect material whose resistance doesn’t change with temperature.
The joke here isn’t even specifically about resistances and electronics, it’s that the real world has all sorts of limitations that when you’re doing things whole in the mathematical world you don’t have to account for, and that’s a hard realisation for Physicists (having gone to study Physics at uni and then half way in my degree changing to Electronics Engineering I can tell you that’s one of the shocks I had to deal with in the transition).
(In a way, it’s really a joke about Theoretical Physicists)
See also the “assuming this chicken is a spherical ovoid” kind of joke.
Retro_unlimited@lemmy.world 3 days ago
I had a potentiometer on a circuit board that adjusted a timer, but I found that the timer varied in timing. I ended up replacing with a few resistors and it corrected the variations.
ThePyroPython@lemmy.world 3 days ago
Mathematically yes. Practically, right now? No.
So you need a resistor of this value for your widget.
For that many places of precision you’re looking at a potentiometer with a 10 nano-ohm precision.
I am not aware of any commercially available resistor that can do that but you could create one using microelectronic structures used for ICs and derive a 10 nano-ohm resistor by design and then chain enough of these elements into a resistor network or potentiometer to create the super precise resistance value you want.
Cool, congratulations.
Now how are you going to use this 10 nano-ohm resistor? What voltage will you be applying across it? What current do you expect it to handle? And therefore what are your power requirements? What are your tolerances, how much can the true value deviate from the designed ideal?
Because power generates heat through losses, and that will affect the resistance value so how tightly do you need to manage the power dissipation?
How will you connect to this resistor to other circuit components? Because a super precise resistor on it’s own is nothing but an over-engineered heating element.
If you tried connecting other surface mount devices (SMDs) from the E24 or even E96 series to this super precise resistor then the several orders of magnitude wider tolerances of these other components alone will swallow any of the precision from your super accurate resistor.
So now your entire circuit has to be made to the same precision else all of your design work has been wasted.
Speaking of which, now your heat management solution now needs to be super precise as well and before you know it you’ve built the world’s most accurate widget that probably took billions of dollars/euros/schmeckles and collaboration from the worlds leading engineers and scientists that probably cost more time and money than the Large Hadron Collider.