Read the manuel that came with your meter.

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To obtain an accurate reading of potential difference with a voltmeter that has finite resistance, understanding the meter's resistance is crucial. Calculating how this resistance impacts the circuit can help clarify its effects. Historically, voltmeters had lower resistance, which could significantly influence circuit behavior, but modern electronic voltmeters typically feature much higher resistance. This advancement minimizes the impact on the circuit, making it less likely to distort readings. Therefore, for accurate measurements, it is essential to consider the voltmeter's specifications and its effect on the overall circuit.
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For voltmeters with a finite resistance placed in a circuit, What can be done to get a correect reading of potential difference? my teacher said you would have to place a resistor between the leads of the voltmeter to get a close to correct reading, but I am just not quite wrapping my head around this idea.
 
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It doesn't make sense to put a resistor across the meter (unless you mean a resistor already in the circuit).

There isn't much you can do other than to learn the resistance of the meter (often stated on the face of the meter) and do some calculations to see how it is affecting the circuit.

At one time this was a serious problem because Voltmeters had something like 20K ohms resistance per volt on the range used. However, electronic Voltmeters usually have much higher resistance due to a field affect transistor on the front end. If you have a modern meter it is unlikely that its resistance is affecting a circuit significantly.
 
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