Is this a short circuit or not?

In summary, the conversation is discussing the behavior of a circuit with a charged capacitor and a voltmeter connected to its terminals. The question is whether a current flows through the voltmeter and if it could cause a short circuit. It is explained that an ideal voltmeter has infinite resistance and therefore no current flows through it. The voltmeter will read the voltage across the capacitor and will not cause a short circuit. The difference between a short circuit and a usual electric resistance is also clarified.
  • #1
Phyba
9
0
My doubt is about the circuit in the picture. The capacitor is charged ans the switch open. There's a voltimeter connected to the terminals of the capacitor.

Does a current flow through the wires of the voltimeter causing a short circuit? If not, what would happen in the circuit described? What would the voltimeter read??

I would really like to understand it.

Thank you very much!
 

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  • #2
Well, actually it could never be a short circuit beacuse the voltimeter has a very high resistance, right? So there is a current and the voltimeter would read 0?

:confused::confused:
 
  • #3
An ideal voltmeter presents an infinite impedance (resistance) to what it's measuring, so no current can flow through it. It's as if the voltmeter could "see" the voltage without ever touching the circuit in any way.
 
  • #4
Phyba said:
Well, actually it could never be a short circuit beacuse the voltimeter has a very high resistance, right? So there is a current and the voltimeter would read 0?

:confused::confused:

What is a short circuit? What is the usual electrical resistance through a short circuit?

As you say, the voltmeter is designed to have a very high resistance, ideally taken as infinite. Ideally, the current through the voltmeter is zero, but in reality there is a very small current passing through it (necessary for the needle to swing to register the voltage across its terminals). But the current is low enough that you can generally consider it not to affect the charge on the capacitor (even if it discharges very slightly through the voltmeter).
 
  • #5
Phyba said:
Well, actually it could never be a short circuit beacuse the voltimeter has a very high resistance, right? So there is a current and the voltimeter would read 0?

:confused::confused:

Yes the Voltimeter has a very high resistance so there will be a very small current. The voltimeter will not read zero. It will read the voltage at the capacitor. That's why it's called a voltimeter.
 

1. What is a short circuit?

A short circuit is an abnormal connection between two or more points in an electrical circuit, resulting in a lower resistance than the normal circuit. This causes a large amount of current to flow, potentially damaging the circuit or causing it to stop working.

2. How can I tell if it is a short circuit?

There are a few ways to determine if a circuit is experiencing a short circuit. One way is to use a multimeter to measure the resistance in the circuit. If the resistance is very low or close to zero, it is likely a short circuit. Another way is to visually inspect the circuit for any damaged or exposed wires that could be causing a short.

3. What causes a short circuit?

Short circuits can be caused by a variety of factors, such as faulty wiring, damaged or exposed wires, damaged components, or incorrect circuit design. They can also be caused by external factors, such as power surges or lightning strikes.

4. How can I prevent short circuits from happening?

To prevent short circuits, it is important to ensure that all wiring is properly installed and insulated. Regular maintenance and inspections of electrical systems can also help identify and prevent potential short circuits. It is also important to use circuit breakers and fuses to protect the circuit from excessive current flow.

5. Can a short circuit be dangerous?

Yes, short circuits can be dangerous as they can cause high amounts of current to flow through a circuit, potentially leading to overheating, fires, or even electrocution. It is important to take precautions and properly diagnose and fix any short circuits to prevent these hazards.

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