The ideal, or theoretical, voltmeter has infinite resistance, which means that, at any measured voltage, there is no current through the voltmeter.
In the practical world, this is impossible, but there are high resistance voltmeters that minimize the error introduced by drawing a current from a circuit. A typical digital voltmeter has 10 to 20 megohms of resistance, and there are high performance versions that can have thousands of megohms of resistance, or more.
Ideal Voltmeter has an infinite resistance so it won't draw current from the circuit, but in real life ideal voltmeter doesn't exist.
A voltmeter must have a very high resistance to measure voltage. A voltmeter is placed in parallel with the element that you are measuring. If the voltmeter has a low internal resistance, then all of the current will flow through the voltmeter instead of the element. You want all of the current to flow through the element, to get an accurate reading of the voltage. Conversely, an ampmeter must have zero resistance, because it is placed in series with the element.
A galvanometer can be converted into a voltmeter by connecting it with very high resistance.
a high resistance in series
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
The purpose of a voltmeter is to indicate the potential difference between two points in a circuit.When a voltmeter is connected across a circuit, it shunts the circuit. If the voltmeter has a low resistance,it will draw a substantial amount of current. This action lowers the effective resistance of the circuit andchanges the voltage reading.
voltmeter
A voltmeter has the large resistance.The voltage across any component can be measured if & only if the terminals of that component will be open and this will we can acheiv if we connect the high resistance voltmeter across the open terminals of that component to measure the voltage.
Use a voltage divider and an standard high input impedance voltmeter connected to the low voltage output tap of the divider. Just check that: a) the voltage divider has enough resistance to minimize loading of the voltage source (The voltage divider resistance should be as high as possible). b) the voltmeter's input impedance is at least 10-20 times larger than the output resistance (impedance) of the divider. If necessary add a high-input impedance amplifier or a transducer between the divider output and the voltmeter. What is high voltage for you?
The Thevenin equivalent circuit of this battery is 1.5V and 0.6 ohms in series. A more exact answer cannot be given without knowing the actual resistance of the 2 meters (I assumed infinite for the voltmeter and zero for the ammeter, as would be for ideal meters).However I would NEVER attempt this test as you describe it, many types of batteries will explode like bombs when shorted (as they would be when an ammeter was placed across them)! The correct way to do this test safely is with just a voltmeter and an adjustable high wattage resistor.
well a voltmeter measures AC and DC voltage. resistance is a term used only for DC voltage, A voltmeter uses a term called Impedance for AC, without it, when you measure across two terminals it would create a short circuit and would blow up the meter. it is basically a safety feature to prevent people from creating short circuits when measuring.
A voltmeter has a very high resistance, allowing only a small amount of current to pass through it when measuring voltage. This current is negligible compared to the current flowing through the circuit being measured, so the voltmeter does not significantly affect the circuit or consume much power.