Ammeters vs. Voltmeters: Understanding Their Purpose and Connection in a Circuit

  • Thread starter MaXiiMo
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In summary, Ammeters are connected in series in a circuit to measure the current going through a specific element and they do have a small amount of resistance. They do not short circuit the component as they are in series. Voltmeters, on the other hand, are connected in parallel to measure the voltage across a component and they have a relatively high resistance.
  • #1
MaXiiMo
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Ok now this might be considered a dumb question for some but I'm really weak concerning electricity and I'm doing AS physics.
Now why are Ammeters connected in series in a circuit and do they have any resistance? I read that they "short" circuit the component. What does short circuit the component mean ?
What about voltmeters? Do they contain any resistance and why are they connected in parallel?
 
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  • #2
MaXiiMo said:
Ok now this might be considered a dumb question for some but I'm really weak concerning electricity and I'm doing AS physics.
Now why are Ammeters connected in series in a circuit and do they have any resistance?
Elements in series will have the same current, so an ammeter in series with another element will tell you the current going through that element.
They do have resistance, but it is usually small enough to neglect. My own ammeter has a resistance that depends on the scale; it is 0.35Ω on the Amp scale, 2.4Ω on mA scale, and 100Ω on the μA scale.
I read that they "short" circuit the component. What does short circuit the component mean ?
It would mean to place a wire or zero-resistance in parallel with the component. Since the ammeter is in series, it does not short the component.
What about voltmeters? Do they contain any resistance and why are they connected in parallel?
Elements in parallel will have the same voltage, so a voltmeter in parallel with another component will read the same voltage as is across that component. The do have a relatively high resistance, for mine it is 10 MΩ.

Hope that helps.
 

1. What is an ammeter and how does it differ from a voltmeter?

An ammeter is a device used to measure the current flowing through a circuit, while a voltmeter measures the voltage across a circuit. In other words, an ammeter measures the amount of electricity passing through a point in a circuit, while a voltmeter measures the force or pressure of the electricity at that point.

2. Why are both ammeters and voltmeters necessary in a circuit?

Ammeters and voltmeters serve different purposes in a circuit. Ammeters are used to measure the current, which is necessary for determining the power consumption and efficiency of a circuit. On the other hand, voltmeters are used to measure the voltage, which is crucial for ensuring that the correct amount of electricity is being supplied to the circuit.

3. Can an ammeter be used as a voltmeter and vice versa?

No, an ammeter cannot be used as a voltmeter and vice versa. This is because they are designed to measure different quantities and have different internal resistances. Attempting to use an ammeter as a voltmeter or vice versa can result in inaccurate readings and potential damage to the circuit and the devices connected to it.

4. How are ammeters and voltmeters connected in a circuit?

Ammeters are connected in series with the circuit, meaning they are placed in the path of the current flow. On the other hand, voltmeters are connected in parallel with the circuit, meaning they are placed across the components being measured. It is important to note that both ammeters and voltmeters have very low resistances, so they do not significantly affect the original circuit.

5. What is the relationship between current, voltage, and resistance in a circuit?

According to Ohm's Law, the current (I) flowing through a circuit is directly proportional to the voltage (V) and inversely proportional to the resistance (R). This means that as the voltage increases, the current also increases, while an increase in resistance will result in a decrease in current. This relationship is crucial for understanding the behavior of an electric circuit and for properly using ammeters and voltmeters in circuit measurements.

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