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A very very tiny amount of the current that would normally flow through the resistor instead flows through the voltmeter, allowing it to make its measurement. For most purposes this very very tiny amount of current can be completely ignored.

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Dell Herzog

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3y ago

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Why does the voltmeter input have a much higher resistance than the current input?

Anything that a voltmeter is measuring has some internal output impedance. If the voltmeter had a low input impedance, these two impedances would form a voltage divider and reduce the voltage measured. The voltmeter has a high input impedance so that it does not affect ("load down") the thing it is measuring.


If the resistance in the circuit is increased what will happen to the current and voltage?

* resistance increases voltage. Adding more resistance to a circuit will alter the circuit pathway(s) and that change will force a change in voltage, current or both. Adding resistance will affect circuit voltage and current differently depending on whether that resistance is added in series or parallel. (In the question asked, it was not specified.) For a series circuit with one or more resistors, adding resistance in series will reduce total current and will reduce the voltage drop across each existing resistor. (Less current through a resistor means less voltage drop across it.) Total voltage in the circuit will remain the same. (The rule being that the total applied voltage is said to be dropped or felt across the circuit as a whole.) And the sum of the voltage drops in a series circuit is equal to the applied voltage, of course. If resistance is added in parallel to a circuit with one existing circuit resistor, total current in the circuit will increase, and the voltage across the added resistor will be the same as it for the one existing resistor and will be equal to the applied voltage. (The rule being that if only one resistor is in a circuit, hooking another resistor in parallel will have no effect on the voltage drop across or current flow through that single original resistor.) Hooking another resistor across one resistor in a series circuit that has two or more existing resistors will result in an increase in total current in the circuit, an increase in the voltage drop across the other resistors in the circuit, and a decrease in the voltage drop across the resistor across which the newly added resistor has been connected. The newly added resistor will, of course, have the same voltage drop as the resistor across which it is connected.


What is the strength of current in each resistor of a series circuit?

The current in each resistor in a series circuit is the same. Kirchoff's Current Law states that the sum of the currents entering a node must add up to zero. The connection between two resistors in a series circuit is a node. The current entering the node from one resistor is equal to the current leaving the node into the next resistor.


What are the applications for a voltmeter?

The primary application of a digital DC voltmeter is to display the amount of DC current present in a circuit. This is particularly handy when troubleshooting problems.


When the current will be short and open circuited?

Open circuit has no current, so does that mean any resistor in series with it, has no current ,so it can be ignored for analysis( v=ir so 0 current means 0 V) for finding lets say the Thevenin equivalent.? Now for Short circuit, do we ignore a resistor in series with the short, because current will take path of least resistance and ignore that resistor? Also can short circuit have voltage through it ?

Related Questions

What effect if any does connecting a voltmeter across a resistor in a circuit have on the current through resistor?

A very very tiny amount of the current that would normally flow through the resistor instead flows through the voltmeter, allowing it to make its measurement. For most purposes this very very tiny amount of current can be completely ignored.


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


What effect if any does connecting an ammeter in series with a resistor in a circuit have on the current though the resistor?

Connecting an ammeter in series with a resistor in a circuit will not affect the current through the resistor. The ammeter measures the current passing through it, so it becomes part of the circuit and simply measures the current flowing through the resistor without changing it.


What is the purpose of the series resistor in a voltmeter?

The purpose of the series resistor in a voltmeter is to limit the current flowing through the voltmeter and protect it from damage due to excessive current.


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.


How can a voltmeter be connected in a circuit, either in series or parallel, to measure the voltage across a component accurately?

A voltmeter can be connected in parallel to measure the voltage across a component accurately. This means connecting the voltmeter in a separate branch of the circuit, directly across the component being measured. This allows the voltmeter to measure the voltage without affecting the current flow in the circuit.


How does an ammeter work?

An ammeter is a low voltage voltmeter in parallel with a small resistance resistor. Current flow through the resistor creates a voltage drop across it which is then measured by the voltmeter.


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.


How do you install a resistor in an DC circuit?

It depends on the purpose for installing the resistor. If the intent is to decrease current flow, the resistor must be connected in series with the load. If the purpose is to increase current flow, the resistor must be connected in parallel with the load. To connect a resistor in series, connect the resistor to one side of the power source, in line with the load. This will decrease circuit current flow. To connect a resistor in parallel, connect the resistor between the positive and negative sides of the power source, which will effectively connect the resistor across the load . This will increase current flow through the circuit. However, before connecting a component in parallel, make sure the increase in current flow will not exceed the current rating of the circuit or fuses/breakers will blow.


A can be used to reduce the current in a circuit?

A resistor.


Does a resistor reduce current or voltage in an electrical circuit?

A resistor reduces the flow of current in an electrical circuit, which in turn affects the voltage across the resistor.


Can a short-circuit be detected by voltmeter?

yes, voltmeter drops to zero as current increases to maximum