Electric circuit, reversing current

In summary: I am pretty sure that it's connected accordingly... but it's possible that there is a meter out there that is different than the rest
  • #1
-EquinoX-
564
1

Homework Statement


Lets say that I have an electric circuit with an amp and volt meter attached to it and i reverse the direction of the current from the power supply.. what will happen to the reading of both the volt meter and the amp meter?


Homework Equations





The Attempt at a Solution



My guess is that the amp meter have the opposite sign of the original one and the volt meter will read the same as the normal one... correct me if I am wrong
 
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  • #2
First of all, the meters must be connected the right way (i.e. the red cable to + -terminal and black to the - -terminal) otherwise it won't show the correct values. But if there was a meter that worked no matter how you connect it, in your case what would the resistance be? Not the value, but the sign?
 
  • #3
it would be negative??
 
  • #4
-EquinoX- said:
it would be negative??

Exactly. Are there resistors that can be negative? If you put negative resistance to Ohm's law V=R*I, you get -V. What does that mean in the circuit and is that effect possible?
 
Last edited:
  • #5
is there such thing as a negative resistance?
 
  • #6
-EquinoX- said:
is there such thing as a negative resistance?

That's the million dollar question! If there were, wouldn't it raise the voltage in the circuit? Is it possible to raise voltage without energy?
 
  • #7
I guess there isn't a way to raise voltage without energy
 
  • #8
-EquinoX- said:
I guess there isn't a way to raise voltage without energy

That's right. So to return to your original question, what the amp and volt meter read? Would they be as you originally thought or would they be altered some way?
 
  • #9
I guess the amp meter would read negative and as well as the volt meter
 
  • #10
-EquinoX- said:
I guess the amp meter would read negative and as well as the volt meter

What does the sign in front of the amp value indicate? Is it just the magnitude of the value or could it be something else?
 
  • #11
the sign indicates the direction of the flow of the current.. so if it were reading positive the first time and negative when we reverse it, means that the current if flowing in the opposite direction now
 
  • #12
Amp meters always read the current so that, what goes in through their "input" and goes out through "output" is positive. After we reversed the current, the meter would have its "input" where the "output" was, because of the current's flow. So if it read negative values, what would that mean?
 
  • #13
as I said the current is flowing in the opposite direction
 
  • #14
-EquinoX- said:
as I said the current is flowing in the opposite direction

No. Eventhough we don't physically alter the amp meter's position, it would reverse its output and input. And that way the negative reading would indicate the current is flowing in the same direction as we started. So: the readings would stay the same, both still positive.

But after all this complicated and perhaps confusing discussion, you should always remember that the meters work only if they are correctly connected and that there aren't meters that would work as we assumed.
 
  • #15
yes that is correct... I am pretty sure that it's connected accordingly...
 

Related to Electric circuit, reversing current

1. What is an electric circuit?

An electric circuit is a path that allows electricity to flow from a power source, through different components, and back to the power source. It is a closed loop that enables the transfer of electrical energy.

2. How does an electric circuit work?

An electric circuit works by using conductive materials, such as wires, to connect different components, such as batteries, resistors, and switches. When the circuit is complete, electrons flow from the negative terminal of the power source, through the components, and back to the positive terminal of the power source.

3. What is reversing current in an electric circuit?

Reversing current in an electric circuit is the process of changing the direction of the flow of electrons. This can be achieved by using a switch or by altering the polarity of the power source. In a direct current (DC) circuit, the current always flows in one direction, while in an alternating current (AC) circuit, the current changes direction periodically.

4. Why would you want to reverse current in an electric circuit?

Reversing current can be useful for various reasons. For example, in alternating current circuits, reversing current allows for the production of electrical energy, which can then be used to power devices. In direct current circuits, reversing current can be used to control the flow of electricity and turn devices on and off.

5. What are some common components used to reverse current in an electric circuit?

Some common components used to reverse current in an electric circuit include switches, diodes, and transformers. Switches allow for manual control of the flow of electricity, while diodes are used to convert AC to DC. Transformers are used to step up or step down the voltage of the current, which can also reverse its direction.

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