An interesting question

[Sarvesaa]

Dear friends,

Today I appeared for a competitive exam where I got this question they are asking the total current through circuit. I have attached the circuit down.

I think you find it interesting.
 

Thank you

[TimFox]

Since, by inspection, there is no voltage across the "diagonal" 5 ohm resistor, and therefore no current through it, the solution is straightforward.

[eugene]

Since, by inspection, there is no voltage across the "diagonal" 5 ohm resistor, and therefore no current through it, the solution is straightforward.

Which I assume is the real reason for the question: to see who does and does not see the symmetry.

[pqass]

How to solve resistor cube problems:

[Sarvesaa]

Yes its straight forward if you know that 3/6 = 3/6 so its simply a balanced wheatstone bridge. Since it is balanced no current flows through the 5 resistor. The total resistance is 6 and the total current is 1 ampere with 6volt battery.

Thank you

Edit The total current is 0.8333 A with 5volt battery as given in the circuit

[pcprogrammer]

Yes its straight forward if you know that 3/6 = 3/6 so its simply a balanced wheatstone bridge. Since it is balanced no current flows through the 5 resistor. The total resistance is 6 and the total current is 1 ampere.

Thank you

With 5V and 6ohm the current is 0.833333333A instead of 1A

[TimFox]

Mid-way through my career, I learned to be careful to use "straightforward" instead of "trivial" when asked for useful solutions to practical problems.

[Sarvesaa]

Doh  in the question paper it was 6v and I am still sticked to that. Very sorry
Yes with a 5v battery it is 0.83333333 A
Thanks for noting that.

[niconiconi]

These kinds of bridge circuits are usually analyzed by using KVL and KCL and writing down the loop equations, but this can be a tedious and cumbersome process. There's an advanced technique called Extra Element Theorem (EET) by R. D. Middlebrook, which allows one to simplify the analysis significantly in some cases.

This Theorem basically allows you to replace an unwanted component in a circuit with an open circuit and a short circuit, then the total input impedance can be calculated immediately using the EET formula. For example, it allows you to derive the general formula for the input impedance of a non-balanced Wheatstone bridge with arbitrary resistor values, without solving a single equation.

[emece67]

.

[Sarvesaa]

Since I am a high schooler I found it interesting.

[armandine2]

You might find the following interesting too

and worth some time to consider - it is puzzling to me, but beginning to make some sense.

... known in my copy of Tietze and Schenk Electronic Circuits as a double centre tap full wave

but also Dual Polarity Full-Wave Centre Tap

https://forum.allaboutcircuits.com/threads/dual-polarity-full-wave-center-tap-rectifier.30066/

[tooki]

Dear friends,

Today I appeared for a competitive exam where I got this question they are the total current through circuit. I have attached the circuit down.

I had a similar problem in class recently, and another approach is wye-delta transformation.

[TimFox]

The wye-delta transformation and the series-parallel impedance transformation are extremely powerful methods for circuit analysis.
I always had a list of these transformation equations prominently on the bulletin board next to my desk before retiring.

[EPAIII]

Yes, once you realize that, the problem is a trivial exercise in series and parallel resistor combinations. Then Ohm's law and done.

Now, substitute the values of 1, 2, 3, 5, 7, and 11 Ohms for each of the resistors, any order you want, and then solve it. That will separate the men from the boys.

Since, by inspection, there is no voltage across the "diagonal" 5 ohm resistor, and therefore no current through it, the solution is straightforward.

Which I assume is the real reason for the question: to see who does and does not see the symmetry.

[PlainName]

These kinds of bridge circuits are usually analyzed by using KVL and KCL and writing down the loop equations, but this can be a tedious and cumbersome process. There's an advanced technique called Extra Element Theorem (EET) by R. D. Middlebrook, which allows one to simplify the analysis significantly in some cases.

This Theorem basically allows you to replace an unwanted component in a circuit with an open circuit and a short circuit, then the total input impedance can be calculated immediately using the EET formula. For example, it allows you to derive the general formula for the input impedance of a non-balanced Wheatstone bridge with arbitrary resistor values, without solving a single equation.

What is is the point of having thumbnails if you're going to hog my screen with the full sized thing as well? The stuff wasn't even interleaved in your text as if if had to go in a specific position.

[T3sl4co1l]

What is is the point of having thumbnails if you're going to hog my screen with the full sized thing as well? The stuff wasn't even interleaved in your text as if if had to go in a specific position.

And now it's quoted to take up double the space and OP can't edit your copy of it. Well done.

Tim

[tooki]

What is is the point of having thumbnails if you're going to hog my screen with the full sized thing as well? The stuff wasn't even interleaved in your text as if if had to go in a specific position.

While it’s true that there was no pressing need to inline the images, surely you must be aware that there’s no way to attach* an image to a post without having the thumbnails, regardless of whether they’re later inserted inline or not.

*meaning attaching it using the forum’s own hosting, not an external hosting provider.

[PlainName]

What is is the point of having thumbnails if you're going to hog my screen with the full sized thing as well? The stuff wasn't even interleaved in your text as if if had to go in a specific position.

And now it's quoted to take up double the space and OP can't edit your copy of it. Well done.

Tim

Yes, that was an intentional example of stuff we see on EEVBlog. You might recall that I am often taking to task for NOT doing the full-fat quote stuff!

[Nominal Animal]

Wait, I'm confused here.  When I attach an image, am I supposed to leave it as an attachment (which means anyone interested has to click on it), or have the expanded version within the body of the message (so that everyone can immediately see what I'm referring to)?  I prefer the latter, but.. 

[PlainName]

Are you serious? Really?

We chat about stuff on EEVBlog. Sometimes an illustration is useful, perhaps a photo or whatever. But those things take up space and are secondary - we may not be arsed to look, and once seen we probably don't need to keep seeing them. This is not pinterest.com, nor is it tiktok.

Photos and stuff don't reflow and take time to download (again!) and make the text of long pages jump around as they get belatedly loaded. The solution is to have thumbnails, which don't get in the way but if one is interested it is really very easy to just click on it and see it in a bigger format.

Doesn't someone keep apologising for walls of text? And yet what we have here is a bloody photo of a wall of text, and it's blown up bigger than normal to boot! Well, that's his choice and it would be fine if it were a thumbnail. Oh, bless my soul, there IS a thumbnail but clearly no-one can be trusted to remember to click that every time the page loads, so he has to fill my page with a photo I'm not interested in any more just so I can get to see what someone actually says.

so that everyone can immediately see what I'm referring to

Sometimes, and it's rare and only when there are a lot of images with explanatory text, a thumbnail embedded in the body of the post is useful. In this case the things were at the end of the text anyway, just ahead of the bloody thumbnails!

But a clever chap like you surely knew all that anyway.

[pcprogrammer]

We chat about stuff on EEVBlog. Sometimes an illustration is useful, perhaps a photo or whatever. But those things take up space and are secondary - we may not be arsed to look, and once seen we probably don't need to keep seeing them. This is not pinterest.com, nor is it tiktok.

And yet at many times when one writes about a problem with a circuit and does not supply the schematic, the first thing that's asked is "where is the schematic, because it makes it much easier to understand what we are talking (actually writing) about".

Or do you have pictures of that, because "they say more than a 1000 words".

 

[Nominal Animal]

Are you serious? Really?

Yes, but not photos of text.  I was more thinking of the schematics I've attached to some of my posts in the Beginner forum.

Doesn't someone keep apologising for walls of text?

Yeah, because I know it irritates some members, and even though I'd like to avoid it, I cannot.  So it is an acknowledgement that my comms style is lacking.

And yet what we have here is a bloody photo of a wall of text, and it's blown up bigger than normal to boot! Well, that's his choice and it would be fine if it were a thumbnail.

I seriously dislike text-as-pictures, because it renders poorly and tends to look like I had soap in my eyes or something.

I honestly didn't know if you (plural, you all) were referring to this particular case, the more general case of funny-but-not-important-to-the-post photos and images, or all images.

But a clever chap like you surely knew all that anyway.

It's not cleverness, it is social awareness.  Only my directness/honesty about it saves me in real life from the gaffes I occasionally make because my social awareness is a bit limited.  Not to any degree of actual diagnosis, but to the degree often encountered in e.g. absent-minded professors and mad scientists.
I wouldn't mind being called a mad scientist, really.

[PlainName]

We chat about stuff on EEVBlog. Sometimes an illustration is useful, perhaps a photo or whatever. But those things take up space and are secondary - we may not be arsed to look, and once seen we probably don't need to keep seeing them. This is not pinterest.com, nor is it tiktok.

And yet at many times when one writes about a problem with a circuit and does not supply the schematic, the first thing that's asked is "where is the schematic, because it makes it much easier to understand what we are talking (actually writing) about".

Or do you have pictures of that, because "they say more than a 1000 words".

 

That's what the attachment facility with thumbnails is for.

[pcprogrammer]

Then you must really hate the TEA thread. That one is full of pictures within the body, and they get quoted a lot