I've been trying to learn about voltage drops, and it didn't help that I tried to learn about LEDs at the same time.
But I think I get it now? So it's not so much that they don't obey omhs law, it's like they turn into a different component when you change the voltage across them.
>>Ohms law always appli-
i'm an electrical engineer. no one ever said "ohms law always applies. It was always presented in the context of purely resistive loads. frick, ohms law doesn't even apply to caps or coils.
>ohms law doesn't even apply to caps or coils.
Yes it does, moron, but with impedance instead of resistance.
Never heard of [math]Z_L = jomega L[/math] and [math]Z_C = 1/j omega C[/math] ?
Z=/=R idiot. at any given time V/I=/=Z either. what you are posting is a phasor which only applies in the monochromatic steady state. to say it's the same as ohms law is moronic. This is "electrons flowing in wires delivers energy" tier moronation.
>monochromatic steady state. to say it's the same as ohms law is moronic
What the frick are you even saying you fricking idiot? Im talking about caps and diodes, theyre are very fricking linear, even their transients are linear because theyre modeled by first order linear odes, the odes come from faradays law and from gauß' law when applied to lumped components. Want me to fricking derive them for you? >Monochromatic steady state
Most jarring thing ive heard in a while, what the frick is up with this boars being filled with schizos and morons?
By the way I am an actual electrical engineer, that has actually worked in power systems, specifically with modelling and simulation of large scale grids for very big fricking industrial plants.
So shut the frick up, moron, for fricks sake
2 years ago
Anonymous
>power systems
No wonder you think that capacitors are Ohmic devices. Assuming you speak German because of the ß: Weißt du, was ein OHM'scher Widerstand ist? Warum heißt der wohl so?
2 years ago
Anonymous
>OHM'scher Widerstand
Kondensatoren haben Ohmnischer Widerstand
Wenigstens, wenn die Frequenz festgesetzt ist
2 years ago
Anonymous
I think, that's exactly what the other guy meant with "monochromatic steady state". Monochromatic = one colour = one frequency; steady = the frequency does not change
2 years ago
Anonymous
Ohms law is a linear relationship between curremt and resistance, and its linear in a capacitor literally for any current.
Who the frick says ohms law and thinks of a relationship w.r.t frequency? thats moronic
2 years ago
Anonymous
By the way only highschool students call V = IR "ohms law" that's literally only valid for purely resistive circuits.
Anyone else uses V = IZ or even J = sigma*D if you want to model an electric field
2 years ago
Anonymous
Jesus, dude, stop making a fool of yourself
2 years ago
Anonymous
>theyre are very fricking linear, even their transients are linear because theyre modeled by first order linear odes
nobody tell this guy the solutions to first order ODEs are exponential functions.
2 years ago
Anonymous
When people say linear they mean the system you absolute animal, not the fricking solutions.
Moreover the solution is an exponential function with respect to time, its not an exponential relationship between voltage and current.
He wants to say it's the fields but the movement of charges is necessary for it so it's mostly just a semantic squabble of no consequence.
2 years ago
Anonymous
How do electrons carry energy
2 years ago
Sam eggy
By their movement being necessary to create the magnetic field needed for there to be electromagnetic energy flux.
You can say that they aren't literally the thing that carries the energy and the exact mechanism is something very interesting but categorically rejecting the idea is a little misleading.
If you studied EM fields you already know this but if you are a layman this statement is just confusing.
2 years ago
Anonymous
I am a freshman electricuck student so I don't know anything but it interests me
2 years ago
Sam eggy
Ah, I see.
I had EMF in my 3rd year of EE. Easily my favourite subject. Very math heavy though.
2 years ago
Anonymous
What book did you use? I've tried to study Griffiths but I can't into 3d calculus yet so I figured I would come back to it after a year or two
2 years ago
Sam eggy
I used books in my language written by my professors so I don't think I can give you any recommendations.
2 years ago
Anonymous
I'll find a voltage meter to measure the difference between an LED and my Tazer and we can talk about V=I/R.
2 years ago
Sam eggy
A diode doesn't have a constant R. A tazer doesn't either for that matter.
2 years ago
Anonymous
>voltage meter >"difference between LED and tazer" >V=I/R
so much about this post is hilarious, bravo
2 years ago
Anonymous
Through kinetic energy
2 years ago
Anonymous
*drifts at [math]10^{-5},mathrm{m/s}[/math]
2 years ago
Sam eggy
Their kinetic energy cannot carry the energy. The electrons in a wire aren't slowing down when the energy is dissipated as heat. For a wire of uniform cross-sectional area and non-zero resistance, their average drift velocity will be constant while the energy is still delivered.
2 years ago
Anonymous
electrons have a charge. charge creates a potential around is (this is called coulomb force and it was discovered hundreds of years ago). electrons can move freely in metal. chemical batteries and dynamos can be used to shunt these electrons. etc.
I really hope you're under 18 for your own sake.
You can make it apply to capacitors. Capacitors still follow [math]V=IR[/math]. The capacitor acts as a voltage source so you have to include it.
I guess an inductor would act as a current source analogous to the capacitor.
>ohms law doesn't even apply to caps or coils.
Yes it does, moron, but with impedance instead of resistance.
Never heard of [math]Z_L = jomega L[/math] and [math]Z_C = 1/j omega C[/math] ?
Not everything is purely a steady-state AC circuit. You can't solve transients like this.
>Not everything is purely a steady-state AC circuit. You can't solve transients like this
Yes you can, DEs for caps and inductors are first order and linear, take laplace transform, you then have
[math](Y/X)(s) = 1/sC[/math] for caps and [math](Y/X)(s) = sC[/math] for inductors.
>Not everything is purely a steady-state AC circuit. You can't solve transients like this.
You do realize that the time dependent expressions for reactances are a thing?
Reduces to [math]I = ZV[/math] for lumped components.
Also, who the frick is actually solving maxwells equations in the real world using a fricking conductivity tensor ?
>Ohms law always applies
yes. name an example in which is doesn. reminder that ohm's is law states: "the current through a resistor is proportional to the voltage over it"
That's not what ohm's law says at all. And even if that was it, that's wrong as well. Current is only proportional to the voltage drop over a component if it's a purely ohmic component. Diodes are not and the current through them does not follow a linear relationship with the voltage.
>That's not what ohm's law says at all
It is precisely what Ohm's law says. https://www.britannica.com/science/Ohms-law >The amount of steady current through a linear material is directly proportional to the potential difference, or voltage, across the material.
What the FRICK do YOU think it says you coping, larping physicslet?
I'd say saying it's just proportional is a little bit incomplete.
Still, I don't know what you are smoking but diodes absolutely do not follow ohm's law.
2 years ago
Anonymous
"The current through a linear material is proportional to the voltage over it."
Diodes are not constructed from linear materials. So Ohm's Law still applies and there is no "violation". I smoke weed and swallow cum homosexual kys
This.
Classical Ohm's law is for idealized lumped elements where R is a constant proportionality factor between voltage and current.
As soon as it changes with time/temperature/power/etc., R is no longer constant and just the derivative of the U-I-curve at any point in time. So Ohm's law still applies, just locally
I still remember blowing a lot of these before realizing I'm colourblind
>Homosexual by disability
Why?
You're so moronic that you didn't even read the fricking law I mean: IT ONLY APPLIES TO OHMIC MATERIALS!!!!! You're so dumb.
Definition of an Ohmic material: material that Ohm's law applies to
Definition of Ohm's law: law that applies to Ohmic materials
It doesn't apply even to some average lamp, mate. I never saw anyone say Ohm's law always applies without also mention WHEN it "always" applies.
I've been trying to learn about voltage drops, and it didn't help that I tried to learn about LEDs at the same time.
But I think I get it now? So it's not so much that they don't obey omhs law, it's like they turn into a different component when you change the voltage across them.
Diodes have an exponential I-V relationship. Resistors have a linear I-V relationship.
Not true.
Exposing myself to morons that can't do science in IQfy, you are quite right.
The relation is more like I=I0(exp(kV)-1). Pretty close tho
>>Ohms law always appli-
i'm an electrical engineer. no one ever said "ohms law always applies. It was always presented in the context of purely resistive loads. frick, ohms law doesn't even apply to caps or coils.
>ohms law doesn't even apply to caps or coils.
Yes it does, moron, but with impedance instead of resistance.
Never heard of [math]Z_L = jomega L[/math] and [math]Z_C = 1/j omega C[/math] ?
>[math]j[/math]
Sorry, I don't speak engineer
>Sorry, I don't speak engineer
Based i enjoyer
Z=/=R idiot. at any given time V/I=/=Z either. what you are posting is a phasor which only applies in the monochromatic steady state. to say it's the same as ohms law is moronic. This is "electrons flowing in wires delivers energy" tier moronation.
>monochromatic steady state. to say it's the same as ohms law is moronic
What the frick are you even saying you fricking idiot? Im talking about caps and diodes, theyre are very fricking linear, even their transients are linear because theyre modeled by first order linear odes, the odes come from faradays law and from gauß' law when applied to lumped components. Want me to fricking derive them for you?
>Monochromatic steady state
Most jarring thing ive heard in a while, what the frick is up with this boars being filled with schizos and morons?
By the way I am an actual electrical engineer, that has actually worked in power systems, specifically with modelling and simulation of large scale grids for very big fricking industrial plants.
So shut the frick up, moron, for fricks sake
>power systems
No wonder you think that capacitors are Ohmic devices. Assuming you speak German because of the ß: Weißt du, was ein OHM'scher Widerstand ist? Warum heißt der wohl so?
>OHM'scher Widerstand
Kondensatoren haben Ohmnischer Widerstand
Wenigstens, wenn die Frequenz festgesetzt ist
I think, that's exactly what the other guy meant with "monochromatic steady state". Monochromatic = one colour = one frequency; steady = the frequency does not change
Ohms law is a linear relationship between curremt and resistance, and its linear in a capacitor literally for any current.
Who the frick says ohms law and thinks of a relationship w.r.t frequency? thats moronic
By the way only highschool students call V = IR "ohms law" that's literally only valid for purely resistive circuits.
Anyone else uses V = IZ or even J = sigma*D if you want to model an electric field
Jesus, dude, stop making a fool of yourself
>theyre are very fricking linear, even their transients are linear because theyre modeled by first order linear odes
nobody tell this guy the solutions to first order ODEs are exponential functions.
When people say linear they mean the system you absolute animal, not the fricking solutions.
Moreover the solution is an exponential function with respect to time, its not an exponential relationship between voltage and current.
charging capacitor transient
V=(1-exp(-t))
i=exp(-t)
lets apply "ohms law"
V/I=exp(t)-1=R
cool, a capacitors resistance is an exponential function of time. so cool ohms law always applies, and these transients are linear.
What delivers energy then?
He wants to say it's the fields but the movement of charges is necessary for it so it's mostly just a semantic squabble of no consequence.
How do electrons carry energy
By their movement being necessary to create the magnetic field needed for there to be electromagnetic energy flux.
You can say that they aren't literally the thing that carries the energy and the exact mechanism is something very interesting but categorically rejecting the idea is a little misleading.
If you studied EM fields you already know this but if you are a layman this statement is just confusing.
I am a freshman electricuck student so I don't know anything but it interests me
Ah, I see.
I had EMF in my 3rd year of EE. Easily my favourite subject. Very math heavy though.
What book did you use? I've tried to study Griffiths but I can't into 3d calculus yet so I figured I would come back to it after a year or two
I used books in my language written by my professors so I don't think I can give you any recommendations.
I'll find a voltage meter to measure the difference between an LED and my Tazer and we can talk about V=I/R.
A diode doesn't have a constant R. A tazer doesn't either for that matter.
>voltage meter
>"difference between LED and tazer"
>V=I/R
so much about this post is hilarious, bravo
Through kinetic energy
*drifts at [math]10^{-5},mathrm{m/s}[/math]
Their kinetic energy cannot carry the energy. The electrons in a wire aren't slowing down when the energy is dissipated as heat. For a wire of uniform cross-sectional area and non-zero resistance, their average drift velocity will be constant while the energy is still delivered.
electrons have a charge. charge creates a potential around is (this is called coulomb force and it was discovered hundreds of years ago). electrons can move freely in metal. chemical batteries and dynamos can be used to shunt these electrons. etc.
I really hope you're under 18 for your own sake.
You can make it apply to capacitors. Capacitors still follow [math]V=IR[/math]. The capacitor acts as a voltage source so you have to include it.
I guess an inductor would act as a current source analogous to the capacitor.
Not everything is purely a steady-state AC circuit. You can't solve transients like this.
>Not everything is purely a steady-state AC circuit. You can't solve transients like this
Yes you can, DEs for caps and inductors are first order and linear, take laplace transform, you then have
[math](Y/X)(s) = 1/sC[/math] for caps and [math](Y/X)(s) = sC[/math] for inductors.
>Not everything is purely a steady-state AC circuit. You can't solve transients like this.
You do realize that the time dependent expressions for reactances are a thing?
What if I told you Resistance doesn't have to be a constant
>he thinks ohm's law is V=IR
J=sigmaE where is sigma is the conductivity tensor blocks your path
Reduces to [math]I = ZV[/math] for lumped components.
Also, who the frick is actually solving maxwells equations in the real world using a fricking conductivity tensor ?
Me every time I make a simple LED circuit.
>Ohms law always applies
yes. name an example in which is doesn. reminder that ohm's is law states: "the current through a resistor is proportional to the voltage over it"
That's not what ohm's law says at all. And even if that was it, that's wrong as well. Current is only proportional to the voltage drop over a component if it's a purely ohmic component. Diodes are not and the current through them does not follow a linear relationship with the voltage.
>That's not what ohm's law says at all
It is precisely what Ohm's law says. https://www.britannica.com/science/Ohms-law
>The amount of steady current through a linear material is directly proportional to the potential difference, or voltage, across the material.
What the FRICK do YOU think it says you coping, larping physicslet?
I'd say saying it's just proportional is a little bit incomplete.
Still, I don't know what you are smoking but diodes absolutely do not follow ohm's law.
"The current through a linear material is proportional to the voltage over it."
Diodes are not constructed from linear materials. So Ohm's Law still applies and there is no "violation". I smoke weed and swallow cum homosexual kys
OI! You aavin' a thread without me?
[math] V=IR [/math]
[eqn] e^{ipi}+1=0 [/eqn]
Why does V = IR not apply to LEDs?
I=exp(v)
why tho
>why tho
read a book on solid state physics.
Even if. Even if I=I0exp(V/V0)
Just put
V=RI
V=RI0exp(v/v0)
R=V/I0exp(V/V0)
-plies you engineer scum. Nobody said R needs to be a constant. R can vary by voltage, by current, by time.
This.
Classical Ohm's law is for idealized lumped elements where R is a constant proportionality factor between voltage and current.
As soon as it changes with time/temperature/power/etc., R is no longer constant and just the derivative of the U-I-curve at any point in time. So Ohm's law still applies, just locally
>So Ohm's law still applies, just locally
what if my diode has a locally non-differentiable V-I curve
don't worry about it, you will never encounter a diode with a non-differentiable V-I curve
You clearly havent mastered the art of pinning measurement errors to parasitic capacitance, go to reading experiment methodology please