Ammeter and voltmeter confusionhelp please

In summary, an ammeter is always connected in series with the resistor(s) because it measures the current passing through the circuit. On the other hand, a voltmeter is always connected in parallel with the resistor(s) because it measures the potential difference between two distinct points in the circuit. If a voltmeter is connected in series, it will essentially block the main current and will not be able to measure the potential difference accurately.
  • #1
moomoocow
14
0
hello
i know why an ammeter is always in series with the resistor(s)
but i don't know why a voltmeter is in parallel with the resistor(s)
can somebody explain this?

thank you:D
 
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  • #2
moomoocow said:
hello
i know why an ammeter is always in series with the resistor(s)
but i don't know why a voltmeter is in parallel with the resistor(s)
can somebody explain this?

thank you:D

If you put a voltmeter in series in a circuit, what voltage would it be measuring? When used in the usual way, you want the meter to not affect the circuit, but it always does have some effect.
 
  • #3
In order to understand this you have to think about what each meter is measuring. I'll assume you know and understand what the ammeter is measuring, so we won't go over that.

The voltmeter, of course, measures voltage. If you remember back to your first physics class, voltage was defined as a potential difference between two points in space. Notice the word "difference." This implies that you need two distinct points in space at two distinct potentials in order to measure a potential difference between them, or a voltage. Voltages are never absolute, they are always measured with respect to something. If you were to hook up a voltmeter in series with a circuit component, you would read zero. This is because you've essentially connected your voltmeter in parallel to one point in the circuit. There can be no potential difference if there is no difference in space.

I hope that helps.
 
  • #4
The Voltmeter is a very high resistance device...if connected in series, it blocks the main current in the circuit completely (resistance in series is greater than resistance when connected in parallel). So when the voltmeter is connected in parallel, only 1/(device resistance) is introduced into the circuit...... which is almost next to zero.
I hope this helped
 

1. What is the difference between an ammeter and a voltmeter?

An ammeter is a device used to measure current, while a voltmeter is used to measure voltage. Current is the flow of electric charge, whereas voltage is the potential difference between two points in an electrical circuit.

2. How do I know when to use an ammeter or a voltmeter?

You should use an ammeter when you want to measure the amount of current flowing through a circuit, and a voltmeter when you want to measure the voltage across a component in a circuit.

3. Can I use an ammeter to measure voltage or a voltmeter to measure current?

No, it is not recommended to use an ammeter to measure voltage or a voltmeter to measure current. This can damage the instruments and give inaccurate readings. It is important to use the correct instrument for the specific measurement.

4. What is the correct way to connect an ammeter or voltmeter to a circuit?

To measure current with an ammeter, it must be connected in series with the circuit, meaning it is placed in the path of the current flow. To measure voltage with a voltmeter, it must be connected in parallel with the component being measured, meaning it is placed across the component.

5. Why do I need to be careful when using an ammeter or voltmeter?

Ammeters and voltmeters are delicate instruments that can be easily damaged if not used correctly. It is important to follow proper procedures and use the correct instrument to ensure accurate readings and avoid damaging the instruments.

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