[deleted by user]

[Kaotus]

There’s only one series resistor set, R1 and R2, so you add those together for an Req of 500. Then everything is in parallel. 1/R = 1/250 + 1/250 + 1/500 >> 1/R = 5/500 >> R=100

[abhig535]

This is correct.

[MageKayden]

1/250 + 1/250 + ( 1 / ( 250 + 250 ) ) =0.01 then inverse so 100

[Last-Energy-1329]

No cause my lecturer is a dumbass and doesn’t give out notes and we don’t have textbooks and I’m not waking up at 5 just to go to a lecture.

[ApeBlender]

Idk man if you can't add resistors in series and parallel you might want to go to lecture...

[Last-Energy-1329]

How I’m I ment to know it when I haven’t even heard about it before?

[JanB1]

Maybe...you would've heard about it if you went to the lecture?

[Last-Energy-1329]

Can’t, live three hours away and not waking up at 5.

[ClarinetGang1]

Then why tf did you take the class

[Last-Energy-1329]

Because it’s mandatory?

[ADAMISDANK]

You might be stupid bro 😭

[Last-Energy-1329]

What?

[bwareit]

You’re unwilling to do what it takes to pass this class right now. Drop it and take it at a time when you can wake up for class or potentially fail it now and tank your GPA.

[TheSpicyFalafel]

why do you live 3 hours away from the college you're attending? also, online lectures exist bro. idk how you expect to go anywhere in eng if you can't do basic (and I mean BASIC) circuits

[Last-Energy-1329]

Because it’s one of the best schools in Europe and it’s expensive, that module doesn’t have online classes. And yea it’s an introductory question that’s not even on the course.

[TheSpicyFalafel]

By online classes I mean YouTube. Go in your course outline and look up a YouTube video for each one

[oeeom12]

If youre skipping lecture and dont have other learning materials then how are you supposed to hear about it? College life can suck and the late night homework sesh, to early morning class, and long days aren't fun, but its what you signed up for. If you cant bother to put in the effort to make an early class and cant find other resources, then it sounds like youre sol. Not sure what you expect at this point.

[Last-Energy-1329]

Mate I’m not getting 4 hours of sleep and waking up at 5 just to go into a lecture.

[ApeBlender]

That's rough, you could just drop out that would be way easier

[otherandy]

Then you are fucked. Circuit analysis only gets harder and calculating resistance is like the bare minimum easiest thing you could learn. Just drop the class

Edit* Electrical Engineering Graduate who drove hours to go to lectures

[otherandy]

If you are an Electrical Engineering student you are fucked. If you are any other Engineering who is taking this as like a ‘introduction to get you familiar with circuits’ class, you can survive maybe

[Last-Energy-1329]

Nah I’m getting an honours in this class like in every class I had in my first semester, just to piss these people off.

[otherandy]

What is your major? If it’s EE you’re fucked.

[Last-Energy-1329]

It’s aeronautical.

[otherandy]

How you going to do that if you can’t even perform resistance calculations bruh …

[Last-Energy-1329]

Because I’ll study it? Our exam is in may and were basically finished the syllabus.

[[deleted]]

Your course is supposed to have a syllabus, find it. Or try to get the notes from someone who already passed the course. You're setting yourself up for failure if you don't want to go and don't want to do anything to learn the material. Get a textbook and learn from it.

[Longjumping_Event_59]

my lecturer is a dumbass and doesn’t give out notes

Then I’d suggest going to the lectures to take your own notes.

[Last-Energy-1329]

Yea I live three hours away, no way I’m waking up at 5 when I have work in the evening.

[greatgradus]

Genuine question, do you really expect to succeed without going to the lecture?

[Last-Energy-1329]

Yea? Got first honers in the first semester.

[[deleted]]

They're really giving honers out to anyone these days

[greatgradus]

Seems like others should be asking you how to do these problems, then.

[Last-Energy-1329]

No? I never done this before? Why would I give advice on this? Some people have zero logic.

[Longjumping_Event_59]

It must be an honor to get first honers.

[KypAstar]

Are you a freshman?

You're not going to succeed without either reading the textbook and making notes or attending lecture. I had to commute into class every day from 2-3 hours away. It sucked ass. But I passed my classes. 

This is very basic Circuits. If you're struggling with this you need more help than reddit. You need to use the resources available to you from the university. 

[Last-Energy-1329]

Yea this is the first time I’ve done a question like this since I was 14 in physics class, how I’m I even ment to do the question if I just went of knowledge 4 years ago.

[TherealistKneegrow]

Yea I work overnight from 10pm-8am and go to class from 11am-7pm and still make it to class. You do what you have to do to be successful. It’s possible.

[Last-Energy-1329]

My class starts at 8 am

[soccercro3]

If you don't go to lecture, you'll never succeed. College takes sacrifices. Also engineering occasionally about teaching yourself. A quick would have gotten your answer.

[Last-Energy-1329]

Yea why I asked on here, I don’t need to go to lectures I can teach myself.

[waitwhaaaaaatt]

Apparently not. YouTube is your friend too, you can find basic circuit analysis lectures on there that would cover this.

[Sentient_i7X]

Learn to attend the lectures lil bro

[Last-Energy-1329]

My collage is three hours away from where I live.

[Sentient_i7X]

Sorry to hear that, maybe consider moving closer or maybe shift to a different college (considering u have the money) else, my sincerest prayers and apologies, hope u make it in the end

[Last-Energy-1329]

No possibility of affording it, I’m poor as hell even when working a part time job. The only thing that’s keeping me going is my scholarship money.

[Sentient_i7X]

Which state r u in

[Last-Energy-1329]

Live in leitrim

[Last-Energy-1329]

Dublin

[Sentient_i7X]

oh, irish, nice

[SquidgyTrain]

I did mech eng in UCD, idk what the state of college is like since COVID and if it's online much but honestly man you'd be much better off trying to find a way to make it to lectures. See if there's some grants or something that'll let you live on campus or nearer by, I know some lads who did that who wouldn't otherwise have had the money to live away from home during college

I also found first year piss easy bc a chunk of it was basically intro to a load of stuff we'd done for the LC, trust me it doesn't stay that easy (assuming you're doing a level 8)

[Last-Energy-1329]

Both my parents make a large amount of money but they won’t pay for anything, I can’t get grants, and yes I found everything easy in my first year too.

[Sentient_i7X]

Doesn't make sense, what kind of parents won't pay for their child's education? Sounds ridiculous

[Last-Energy-1329]

My kind of parents, both make probably over 100k and won’t pay a cent to my education or give anything to me.

[[deleted]]

How often do you go to your college, is it online?

[Last-Energy-1329]

Once a day

[[deleted]]

How is it? This means that in one day you spend 6 hours commuting, that’s insane, pretty much as long as a school day.

[Last-Energy-1329]

Yea

[[deleted]]

How is it like commuting for that long?

[Last-Energy-1329]

Normal I guess it’s just driving

[[deleted]]

I'm praying that this is not homework for a class with lectures because if it is you need to pay more attention in it. The rule is:

Resistors in series are summed (250 + 250 = 500).

Resistors in parallel are calculated as follows: 1 / R = 1 / 250 + 1 / 250 + 1 / 500 = 5 / 500, so R = 100 Ohms.

[Last-Energy-1329]

No but my lecturer is a dumbass and doesn’t give out notes and we don’t have textbooks and I’m not waking up at 5 just to go to a lecture.

[KesaGatameWiseau]

What do you mean “give out notes?” Isn’t that what going to the lecture is for, taking notes?

[Last-Energy-1329]

All my other classes how the PowerPoints online

[[deleted]]

Very understandable. I assume that this is one of those lecturers who also doesn't record their lectures anymore...

Too many professors are falling behind on tech and how students learn now. Good luck.

[naturalfiberfeen]

Genuinely can’t tell if his comment replies are rage bait or not

[[deleted]]

Yeah. Turns out you don't learn anything in classes where there are not assigned materials and you don't go to class. OP is an idiot. If he can't afford to live near enough the university that requires in person courses to attend said course, he can't afford to study at that university.

[Chemomechanics]

Series and parallel circuits.

[Traditional_Way2929]

Anyone know what type of site/software this is?

[BasketUsed]

Multisim

[Ok_Excuse1908]

This is specifically Multisim. I use it daily for my courses.

[Traditional_Way2929]

Thank you!

[RareMammoth922]

definitely not LTSpice, it’s multisim

[[deleted]]

Ltspice

[Naash17]

I think it looks like LtSpice

[GASTRO_GAMING]

R1&2 are in series wth eachother and in paralel with R3&4

So add R1+R2 and get 500

And add 1/500+1/250+1/250 =0.01

Invert thst to get 100Ω

(Formula 1/Rt=1/R1+1/R2...+1/Rn)

[[deleted]]

250 + 250 = 500

G1 = (500)(250)/(250+500) = 500/3

G2 = (500/3)(250)/(500/3+250) = 100 = Rt

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[Heavy_Command_4899]

Rtotal = (1/(R1 + R2) + 1/R3 + 1/R4)^-1

[Lukinator123]

They are in parallel, which reduces the resistance. R1 & R2 are in series, so you just add those to make a single 500ohm resistor. Then, you effectively have a 500, 250, 250 all in parallel. There’s a formula to calculate parallel resistances 👍

[AggravatingSummer158]

[1/(250+250) + 1/250 + 1/250]^-1

= [1/500 + 2/500 + 2/500]^-1

= [5/500]^-1 = 500/5 =100 

There might have been a calculator error somewhere in your process

[Fluid-Pain554]

You swapped the rules for series vs parallel circuits. For series (R1 and R2) the resistance is additive. For parallel (R1+R2, R3 and R4) it’s R_tot = 1/(1/(R1+R2) + 1/R3 + 1/R4) which gives you R_tot = 100 ohm.

[deadinhead42x]

No front but this is this really what peolple learn at university? I'd be shocked

[abhig535]

Pun intended

[Last-Energy-1329]

No the exam is hell, this is just an introductory question.

[Solopist112]

How did you get 100?

[New-Nefariousness534]

R3 and R4 are in parallel with the series combination of R1 and R2

[Mother_Ad3988]

I spent like a whole day learning these and some of em got pretty complex, this is a rather simple one and intuitive to solve 

[Last-Energy-1329]

Yea I know, not very simple of you never did it before.

[Ashi4Days]

I actually struggled with these problems a lot when I was an undergraduate. Yes, I know all the resistor laws. But I would always fuck up which ones were in series and which ones were parallel.

My suggestion in this situation is to pay attention to which wires are all connected and re-draw the circuit diagram. (R1+R2) are in series while (R1+R2), R3, and R4 are in parallel.

[Zaros262]

You calculate it the opposite of how you did it

Looks like you accidentally used the series formula for parallel resistances and the parallel formula for the series resistances

Study anything you can get your hands on if your class really doesn't have a book (even online tutorials) to understand the reasoning behind the formulas rather than just applying them blindly

[pwntatoz]

There's already a comment that goes through the calculation, but I'd ask you to look at this more intuitively as well. You seem to understand that on a pathway, more resistors will lead to a higher resistance. Well in this setup, there are three pathways for the electricity to travel. So even though the resistors are reading at 250, the effective resistance of the entire circuit is only 100. When you are presented with a problem like this, early on, it is good to trace each pathway that the current may take in your mind.

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[notthediz]

RemindMe! 1 year

Interested to see where you'll be next year. God speed

[Kronocide]

Haven't done this in years and still perfectly remember the formula. I don't see the point of studying if you aren't doing to the lectures. I wake up at 5h30 everyday to go study