# Problem in identifying a short circuit in a diagram

• Amaelle
In summary: The requirement was to have a "T" intersection with a dot for each of the 3 connections.In summary, the conversation was about simplifying a circuit diagram and finding the current i(t). The person simplified the diagram by considering R4 and R2 as parallel, but the solution did not consider them as parallel and instead said they were short circuited. The expert suggested labeling the nodes and using Millman's theorem. The person was able to solve their problem with the help of the expert's advice. The conversation also briefly discussed the creation of circuit diagrams and how to make them more readable.
Amaelle
Hi all!
while simplifying this diagram, I thought that R2 and R4 are in parallel
while

so I simplified the diagram to this

BUT THE SOLUTION CONSIDER THAT R4 AND R2 HAVE BEEN COUR CIRCUITED!
Any help would be highly appreciated particularly a rule of thumb that helps me to identify a short circuit with a fault!

In your top schematic, R5 R4 R2 R3 all share a common node. In your "simplified" schematic, this feature has been lost, so it is not equivalent.

Amaelle
thank you! BUT HOW COULD THEY SAY THAT R4 AND R2 ARE SHORT CIRCUITED?

DID they say, "R4 and R2 are court circuit" ? Else what did they actually say or show in a diagram?

They are in parallel. They are significant and not short circuited. But your diagram is in no way equivalent to the original circuit. You have removed the connection between R3 and R5. In your diagram you have connected R3 to the opposite end of R2 and R4 from the original diagram.

I would suggest you label the nodes and note which nodes the components connect to.

Last edited:
Amaelle
let start from the begining:
the exercice ask to calculate the current i(t)

so i simplified the circuit as follow considering that R4 and R2 are parallel ( the circuit is not equivalent to the first but i guess the value i(t) will not change (please correct me if I'm wrong)
then I simplified further the circuit by using the conversion between the current generator a1(t) and it's voltage generator equivalent

after this step I used millman theorem to compute the potential between the nodes 4 and 3
and then divide by the resistance of the branch to find i(t)

the problem is that in solution they totally ignore R4 and R2 as they short circuited!

Merlin3189
If you begin with:

and combine R2 with R4 you get this:

Amaelle
you are awsome! thanks a million you totally solved my problem! God bless you!

gneill
gneill said:
If you begin with:

gneill,
I know it's off-topic, but what did you use to create those circuit diagrams? They look nice, and it seems like you were able to draw them quickly.

eq1 said:
gneill,
I know it's off-topic, but what did you use to create those circuit diagrams? They look nice, and it seems like you were able to draw them quickly.
I use an ancient copy of Visio. I created my own template for electronic symbols (the one that came with Visio was incomplete a rather crude).

Also a bit off topic:
For more readable schematics avoid any connections that have 4 "wires" leaving from a single node. Try to make all connections "T intersections" with large dots. This avoids the confusion of whether connections are joined or crossing. Then all 4 wire nodes are crossing, by definition.
Back in the day this was an absolute Mil-Spec requirement for schematics because poor quality reproductions could add or remove the dots that indicate connections.

sophiecentaur and Merlin3189

## 1. How do you identify a short circuit in a diagram?

To identify a short circuit in a diagram, you first need to understand the components of the circuit and their connections. Look for any components that are connected directly to each other or have a very low resistance between them. These could indicate a short circuit.

## 2. What causes a short circuit in a diagram?

A short circuit occurs when there is an unintended connection between two points in a circuit, resulting in a low resistance path. This can be caused by damaged or faulty components, incorrect wiring, or physical damage to the circuit.

## 3. How can I prevent short circuits in a diagram?

To prevent short circuits in a diagram, it is important to carefully plan and design the circuit before building it. Use appropriate components and wiring techniques, and always double check your work before powering on the circuit. Regular maintenance and inspections can also help prevent short circuits.

## 4. Can a short circuit damage other components in a diagram?

Yes, a short circuit can cause damage to other components in a diagram. The high current flow through the short circuit can overload and damage components, and the heat generated can also cause damage. It is important to identify and fix short circuits as soon as possible to prevent further damage.

## 5. How do you fix a short circuit in a diagram?

The first step in fixing a short circuit in a diagram is to locate the source of the short circuit. Once identified, the damaged or faulty components should be replaced. It may also be necessary to rewire or rearrange components to ensure there are no unintended connections. Always double check your work before powering on the circuit again.

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