# Placing a current direction in a schemactic for exams purposes

#### kleberpaulo

Joined Nov 20, 2019
8
Hi everyone,

I'm a professor in electrical courses. Often, to assess students' knowledge through an exam, I elaborate questions with schematics and ask to find the current and voltage values. Sometimes, I already put the direction of the current or the polarity of the voltage requested in the question, however, to do this, I use some simulation programs - like multisim - and do a workaround to put the arrows of the electric current or the plus minus signs of the voltage.

Is there a program that elaborates schematics and places these arrows and polarities in a more "quick and easy" way? Some for didactic purposes...

#### Papabravo

Joined Feb 24, 2006
14,412
Hi everyone,

I'm a professor in electrical courses. Often, to assess students' knowledge through an exam, I elaborate questions with schematics and ask to find the current and voltage values. Sometimes, I already put the direction of the current or the polarity of the voltage requested in the question, however, to do this, I use some simulation programs - like multisim - and do a workaround to put the arrows of the electric current or the plus minus signs of the voltage.

Is there a program that elaborates schematics and places these arrows and polarities in a more "quick and easy" way? Some for didactic purposes...

IMHO there is no point to doing this. The direction you choose for setting up a problem doesn't care about the directions you choose, but the answer does. Working the problem makes it obvious what the directions should be.

Joined Jul 18, 2013
21,426
Then of course there is the Electron flow or conventional flow issue!
Max.

#### kleberpaulo

Joined Nov 20, 2019
8
IMHO there is no point to doing this. The direction you choose for setting up a problem doesn't care about the directions you choose, but the answer does. Working the problem makes it obvious what the directions should be.

My point is only visual and only for didactic purposes. When solving a circuit (finding currents and voltages), obviously any student will find these directions (standard or not) and polarities, but the idea is to request the value of a particular current, for example, and the direction of that particular current is visually indicated in the schematic.

I have attached a PNG to display this concept.

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#### OBW0549

Joined Mar 2, 2015
3,551
Is there a program that elaborates schematics and places these arrows and polarities in a more "quick and easy" way?
Not that I know of. I doubt one exists.

#### Papabravo

Joined Feb 24, 2006
14,412
In a schematic drawing package you can create custom symbols that you can place manually on a drawing to your heart's content.

#### KeepItSimpleStupid

Joined Mar 4, 2014
4,211
There's no point. But it has to be understood if conventional current is being used. You put an arrow with an arbitrary direction and say "conventional current" so there is no ambiquities. The arrow points to the + direction.

Otherwise your asking for trouble.make a blanket statement in the beginning of the glass about conventional current is the norm in this glass and leave it be.

#### kleberpaulo

Joined Nov 20, 2019
8
There's no point. But it has to be understood if conventional current is being used. You put an arrow with an arbitrary direction and say "conventional current" so there is no ambiquities. The arrow points to the + direction.

Otherwise your asking for trouble.make a blanket statement in the beginning of the glass about conventional current is the norm in this glass and leave it be.
I put the arrow in the schematic just so that the student can visually find out what electrical current was requested in the exam. Just for that.

I have been asking some questions in this way, and, certainly, all conditions are highlighted in the exam so that there is no doubt.

Anyway, thanks for the reminder! I'll take into account.

#### djsfantasi

Joined Apr 11, 2010
6,811
So don’t place an arrow. Highlight the segment containing the current you are looking for. Let the student use any arbitrary standard they wish as long as they can defend their choice. Might be a better measure of the students understanding.

#### KeepItSimpleStupid

Joined Mar 4, 2014
4,211
Hey, i took an exam and gave the wrong answer. I defended by "wrong answer" and won under the grounds of "Your not supposed to know that yet.

Get the conventional and electron current fiasco as soon as one is able to understand it. In chemistry, it gets in the way, We have a way of dealing with it in solid state physics.

So, if I tell you that wiggling a wire in air generates a current, would I be wrong or right?

Physics tells you that your moving a wire in a magnetic field.

Are three resistors, R, in series equlivelent to one resistor, 3*R? I'll tell you no.

are 3 SMT resistors in series mounted on their smaller edges the same as 3 mounted on their larger edge counterpart? No.

Is air a good insulator? depends?

When assemblig a PCB, can you touch it with your fingers?

Ever hear of a "vented screw"? A regular screw in a blind hole is a leak. A fingerprint outgasses.

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#### kleberpaulo

Joined Nov 20, 2019
8
So don’t place an arrow. Highlight the segment containing the current you are looking for. Let the student use any arbitrary standard they wish as long as they can defend their choice. Might be a better measure of the students understanding.
I think there is a misunderstanding here.

The exams are placed at a gradual level of difficulty. Students are always encouraged to interpret all the results obtained, always with the aim of not memorizing methods. For example, there are questions that I "arbitrarily" choose a direction of the current precisely to have such an "interpretation". I ask the student: "if the current value is negative - conventional direction - what is your interpretation of the results? Can the result be considered" wrong "?" Only that. The idea is to impose, in only a few cases, a type of result that encourages interpretation. Obviously I use other ways to approach these results and answers and this is just one of them. I have had good results with this gradual approach.

The gradual difficulty allows the student to solve any circuit, without decorating any method. That's the most important. The student must be fully aware of the nature of what is being calculated and the manner in which it is to be done.

Just to add and clarify: There are still questions that have no arrows or polarities. None. No methods are required to resolve the issues. In the classroom, only the student, the exam and the different ways to solve the same circuit. This brings great results, because I discuss in the classroom the most advantageous methods for each question.

Thanks for your considerations. Be great.

#### kleberpaulo

Joined Nov 20, 2019
8
Hey, i took an exam and gave the wrong answer. I defended by "wrong answer" and won under the grounds of "Your not supposed to know that yet.

Get the conventional and electron current fiasco as soon as one is able to understand it. In chemistry, it gets in the way, We have a way of dealing with it in solid state physics.

So, if I tell you that wiggling a wire in air generates a current, would I be wrong or right?

Physics tells you that your moving a wire in a magnetic field.

Are three resistors, R, in series equlivelent to one resistor, 3*R? I'll tell you no.

are 3 SMT resistors in series mounted on their smaller edges the same as 3 mounted on their larger edge counterpart? No.

Is air a good insulator? depends?

When assemblig a PCB, can you touch it with your fingers?

Ever hear of a "vented screw"? A regular screw in a blind hole is a leak. A fingerprint outgasses.
I understand your considerations, and I appreciate it, but I think there is a misunderstanding.

I don't intend to discuss approaches or methods of exam assessment here. I just say that, with total certainty, students are encouraged to interpret any type of result, any number, meaning, polarity, without memorizing any method. I put an arrow just to impose a type of result that brings some discussion in the classroom.

Some enlightenment:

I think there is a misunderstanding here.

The exams are placed at a gradual level of difficulty. Students are always encouraged to interpret all the results obtained, always with the aim of not memorizing methods. For example, there are questions that I "arbitrarily" choose a direction of the current precisely to have such an "interpretation". I ask the student: "if the current value is negative - conventional direction - what is your interpretation of the results? Can the result be considered" wrong "?" Only that. The idea is to impose, in only a few cases, a type of result that encourages interpretation. Obviously I use other ways to approach these results and answers and this is just one of them. I have had good results with this gradual approach.

The gradual difficulty allows the student to solve any circuit, without decorating any method. That's the most important. The student must be fully aware of the nature of what is being calculated and the manner in which it is to be done.

Just to add and clarify: There are still questions that have no arrows or polarities. None. No methods are required to resolve the issues. In the classroom, only the student, the exam and the different ways to solve the same circuit. This brings great results, because I discuss in the classroom the most advantageous methods for each question.

Thanks for your considerations. Be great.

Thanks for your considerations. Be great.

#### KeepItSimpleStupid

Joined Mar 4, 2014
4,211
An arrow makes no sense unless you define what the arrow means. e.g. the direction of the arrow points to the positive direction of "conventional or electron current". Without that I can argue any answer and win.

#### kleberpaulo

Joined Nov 20, 2019
8
An arrow makes no sense unless you define what the arrow means. e.g. the direction of the arrow points to the positive direction of "conventional or electron current". Without that I can argue any answer and win.
And you really think that I don't define what this "arrow" means. Cute. But ok.

Be fine! Thank for your help!

#### WBahn

Joined Mar 31, 2012
26,148
Hi everyone,

I'm a professor in electrical courses. Often, to assess students' knowledge through an exam, I elaborate questions with schematics and ask to find the current and voltage values. Sometimes, I already put the direction of the current or the polarity of the voltage requested in the question, however, to do this, I use some simulation programs - like multisim - and do a workaround to put the arrows of the electric current or the plus minus signs of the voltage.

Is there a program that elaborates schematics and places these arrows and polarities in a more "quick and easy" way? Some for didactic purposes...

I wish. If you find one, let us know. Maybe there's one out there now or will be someday. The problem is that it is a matter more of artistic presentation than anything else. What currents do you want annotated on the diagram? What voltages? What labels do you want used? Defining those actually wouldn't be too difficult, but then there's the question of placement and style. Exactly where we place a current arrow on a diagram can sometimes convey meaning -- or perhaps I should say emphasis. Also, automated tools have traditionally done a pretty lousy job of placing text and symbols so that they are well laid out. But tools for doing these kinds of things, in general, are getting better. So there is hope.

#### kleberpaulo

Joined Nov 20, 2019
8
I wish. If you find one, let us know. Maybe there's one out there now or will be someday. The problem is that it is a matter more of artistic presentation than anything else. What currents do you want annotated on the diagram? What voltages? What labels do you want used? Defining those actually wouldn't be too difficult, but then there's the question of placement and style. Exactly where we place a current arrow on a diagram can sometimes convey meaning -- or perhaps I should say emphasis. Also, automated tools have traditionally done a pretty lousy job of placing text and symbols so that they are well laid out. But tools for doing these kinds of things, in general, are getting better. So there is hope.
I've been looking for such a solution for a long time. I've used several types of tools but none of them achieves this aspect in an easy and presentable way. Obviously because it is not the focus of these tools. I keep looking.

I found this solution more "presentable", it just isn't GUI oriented. I am setting up some circuits with it for testing.

Perhaps you can use one of those LaTex based circuit drawing tools, though I'm not sure if that qualifies as quick and easy.
https://tex.stackexchange.com/questions/442023/how-to-draw-arrows-to-circuits-in-latex
In case I find any solution, I say here.

Thanks for the reply!

#### Janis59

Joined Aug 21, 2017
1,227
Only alone place where the current direction is essential is the branched circuit calculus with means of Kirchoff laws. However, there are no any harm if ALL simultaneously directions are reverted. Just choose a ONE direction and keep it. If is was wrong, the output will show the minus sign, but calculated current value will be correct.

#### andrewmm

Joined Feb 25, 2011
574
As I understand it, the OP wanted to be able to make diagrams to us in class / exams.
and wanted to know does there exist a program that make sit easy for them.