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Aim of any measuring instrument is to measure the object without affecting it. Voltmeter is used to measure voltage between two points and connected in parallel. Thus voltmeter should not change the voltage. If voltmeter resistance is very high, it will be as good as infinity compared to load. Thus connecting voltmeter will not change the voltage and measure it accurately.
Wiki User
∙ 15y ago
Wiki User
∙ 9y agoIf you use a series resistance equal to the voltmeter resistance, then an external voltage is split equally between the voltmeter and the resistance since the same current flows through both (even though in a good voltmeter that current is very small). So you can apply twice the voltage to get full scale deflection. In the end, it is current which causes the meter to register. So for a meter resistance R and a series resistance r, the voltage range of the meter is multiplied by the ratio (R+r)/R.
Wiki User
∙ 12y agoThe reason is that if the impedance were low that would act as an additional load on the circuit being measured and provide a false reading.
Further information
Since voltmeters are always connected in parallel with the component or components under test, any current through the voltmeter will contribute to the overall current in the tested circuit, potentially affecting the voltage being measured.
A perfect voltmeter has infinite resistance, so that it draws no current from the circuit under test. However, perfect voltmeters only exist in the pages of textbooks, not in real life!
Wiki User
∙ 11y agowhy we replace the analog instruments by digital instruments
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Voltmeter is connected in parallel with resistor?
A voltmeter can be connected in parallel with a resistor to show the voltage across the resistor.
High resistance in parallel connected with galvanometer to form voltmeter?
That won't work. To convert an ammeter (a galvanometer is a very sensitive type of ammeter) you connect a high value resistor in series with it.
How should voltmeter be connected to measure the potential difference across a resistor - in series or in parallel?
In parallel.
A galvanometer can be converted into a voltmeter by placing?
a high resistance in series
How is an ammeter converted to a voltmeter?
The ammeter is used in series, because you want to measure the current through a circuit. The voltmeter is used in parallel, because you want to measure the voltage across a circuit. If you were to place the voltmeter in series, no current would flow because of the relatively high impedance of the voltmeter. If you were to place the ammeter in parallel, you would create a short-circuit, due to the relatively low impedance of the ammeter.
Voltmeter is connected in parallel with resistor?
A voltmeter can be connected in parallel with a resistor to show the voltage across the resistor.
High resistance in parallel connected with galvanometer to form voltmeter?
That won't work. To convert an ammeter (a galvanometer is a very sensitive type of ammeter) you connect a high value resistor in series with it.
How should voltmeter be connected to measure the potential difference across a resistor - in series or in parallel?
In parallel.
Is it possible to apply voltmeter across a variable resistor?
Of course. A good voltmeter can be applied across anything, since its impedance is high and its presence has no effect on the operation of the circuit. When it's connected across a variable resistor, the voltmeter most likely reveals a changing voltage as the resistor is varied.
A galvanometer can be converted into a voltmeter by placing?
a high resistance in series
What path will the current takes in a series circuit with a voltmeter pause does the current goes through voltmeter pause because if it does pause isn't current suppose to be taking the shortest path?
A voltmeter is designed to operate like a very large resistor (order of megaOhms), in parallel to the circuit that it is measuring. As long as the voltmeter resistance is much larger than the circuit that it is measuring, it will draw very little current away from the circuit and will only minimally disturb the operating circuit. See related link. If the voltmeter is connected in series with the rest of the circuit, then that is the same as connecting a very large resistor in series.So for example if you have 10 volt battery and a 10 ohm resistor, that would be 1 amp (without the voltmeter). Now if the voltmeter is 10 megaohm, the total resistance is 10000010 ohms, so the current is 0.999999 microamperes, and the voltage across the 10 ohm resistor is 9.99999 microvolts, while the voltage across the voltmeter is 9.999990 Volts (these numbers are rounded, but you get the idea).Suppose you put in series with a 1 kiloOhm (not sure about that spelling) resistor. The total resistance is 10001000 ohms, and current is 0.99990 microamperes, the voltage across resistor is now 0.9999 millivolts (it was microvolts) and the voltage across the voltmeter is 9.9990001 volts
Voltmeter in series?
No. Voltmeter in parallel. Ammeter in series.
How is an ammeter converted to a voltmeter?
The ammeter is used in series, because you want to measure the current through a circuit. The voltmeter is used in parallel, because you want to measure the voltage across a circuit. If you were to place the voltmeter in series, no current would flow because of the relatively high impedance of the voltmeter. If you were to place the ammeter in parallel, you would create a short-circuit, due to the relatively low impedance of the ammeter.
Why do you get different results when calculating the voltage drop across a resistor and ignoring resistance of a voltmeter and when considering it?
Voltage drop is the product of current and resistance. When you connect a voltmeter across a resistor, you are connecting that voltmeter's internal resistance in parallel with that resistor. The resulting resistance of this parallel combination is lowerthan that of the resistor. As a result the voltage drop (current times this lower resistance) will be lower than it would be without the voltmeter connected. This is called the 'loading effect' of that voltmeter.The higher the internal resistance of the voltmeter, the less effect it will have on lowering the overall resistance when connected across a resistor. This is why the internal resistance of a voltmeter is made deliberately very high. Under most circumstances, therefore, a conventional voltmeter will have very little effect on the resistance of the circuit being tested and, so, it will have no significant effect on the voltage appearing across the resistor.However... for circuits that already have exceptionally-high resistance values, you must be careful when you select a voltmeter as you must take into account its internal resistance and ensure the voltmeter you use has the very highest internal resistance available. This is because the loading effect increases with circuits that have a high resistance. That might involve selecting a voltmeter that works on a completely-different principle , such as an electrostatic voltmeter or, perhaps, an oscilloscope
How do you convert voltmeter to ohmmeter?
First you will need a constant current source. Do NOT connect the voltmeter to the constant current source without the resistor to be measured already connected. Do NOT use a battery, it is a voltage source. Then follow these steps to measure a resistor:connect the voltmeter across the resistor to be measuredconnect the voltmeter-resistor combination across the constant current sourceread the voltmeter and record the voltagedisconnect the voltmeter-resistor combination from the constant current sourcedisconnect the voltmeter from the resistorcalculate the resistance from the measured voltage and current from the source with Ohm's law in this form: R = V ÷ IIts much easier to just use the ohms setting on a multimeter.
What type of meter would be connected on both sides of a resistor in a circuit?
ammeter in series at any side as required since it is bilateral and voltmeter is connected in parallel to measure voltage drop across it
How is the potential difference across a resistor measured?
by using voltmeter
