Answer to Question #217594 in Mechanics | Relativity for Pls help me gradua

Question

The voltmeter (V) is connected in parallel with the device. The ammeter (A) is connected in series in the circuit so that all current passing through the circuit must pass through and be measured by the ammeter.

Answer 1

A voltmeter is connected in parallel with a device to measure its voltage, while an ammeter is connected in series with a device to measure its current. At the heart of most analog meters is a galvanometer, an instrument that measures current flow using the movement, or deflection, of a needle.

The ammeter must have a very low resistance because it is connected in series because we want all the circuit current to go through it to measure the current accurately. The lower the resistance the better so it affects the circuit conditions a minimum possible.

It would not be an accurate measurement if the ammeter resistance alters the current flowing in the circuit when we connect it in the circuit too much.

The voltmeter has a very high resistance for the same reason. The higher the better. So we affect the circuit conditions the least amount when we connect the meter to the circuit to measure a voltage.

Now if we were to connect the ammeter across the load (in parallel ) like we would a voltmeter is connected we will short circuit the supply. That is not a good thing.

If we were to connect the voltmeter in series like we would connect an ammeter in a circuit then very little current will flow. The circuit will not work. So it changes the circuit conditions and means our reading will be highly inaccurate

When we connect meters in the circuit to take measurements we want as accurate measurements possible. Any resistance in series changes the circuit current as does a resistance in parallel affects the voltage across the point we wish to measure.. The least change the better.

High quality ammeters and voltmeters affect the circuit the least for higher accuracy.