- #1
damosuz
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When I connect a AA rechargeable battery directly to a voltmeter, voltage increases slowly, regardless of the way I connect it. I can't figure out why.
Battery voltage increases when voltmeter connected
In summary, when connecting a AA rechargeable battery directly to a voltmeter, the voltage increases slowly regardless of the method of connection. This can be caused by a dying battery in the voltmeter or the heat from a hand can also boost the chemical reaction in the battery, leading to an increase in voltage.
- #2
berkeman
Mentor
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Increases from what to what? And what do you mean by "regardless of the way I connect it"? There aren't that many ways to connect a DVM to a battery...damosuz said:
- #3
OmCheeto
Gold Member
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This happened to me last year when I was measuring the voltage on a car battery.damosuz said:
It turned out the battery in my voltmeter was going dead.
Replacing the battery in the voltmeter made the problem go away.
- #4
CWatters
Science Advisor
Homework Helper
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Sometimes the heat from your hand is enough to boost the chemical reaction in the battery increasing the voltage.
- #5
Averagesupernova
Science Advisor
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Correctly anyway. I wondered the same thing.berkeman said:Increases from what to what? And what do you mean by "regardless of the way I connect it"? There aren't that many ways to connect a DVM to a battery...
1. How does connecting a voltmeter affect the voltage of a battery?
When a voltmeter is connected to a battery, it creates a closed circuit which allows the flow of electrons from the battery to the voltmeter. This flow of electrons causes a drop in the voltage of the battery, leading to an increase in voltage measured by the voltmeter.
2. Why does a battery's voltage increase when a voltmeter is connected?
This increase in voltage occurs because the voltmeter has a very high resistance compared to the battery. As the electrons flow through the voltmeter, they encounter this high resistance, causing a voltage drop. This voltage drop is then measured by the voltmeter as an increase in voltage.
3. Does connecting a voltmeter affect the accuracy of the voltage reading?
Yes, connecting a voltmeter can affect the accuracy of the voltage reading. As mentioned before, the voltmeter has a high resistance which can cause a voltage drop. This can lead to a slightly higher voltage reading than the actual voltage of the battery. However, most voltmeters have a very small resistance and are designed to minimize this effect.
4. Is there a limit to how much the battery's voltage will increase when a voltmeter is connected?
Yes, there is a limit to how much the voltage will increase when a voltmeter is connected. This limit is determined by the internal resistance of the battery. As the current flows through the voltmeter, it also encounters the internal resistance of the battery, which can cause a decrease in voltage. Once the voltage drop due to the internal resistance equals the voltage increase from the voltmeter, the voltage will reach a steady state.
5. Can connecting a voltmeter damage a battery?
In most cases, connecting a voltmeter will not damage a battery. However, if the voltage reading is being taken while the battery is being charged or discharged, connecting a voltmeter can disrupt the charging or discharging process. In extreme cases, this can cause damage to the battery. It is important to disconnect any external devices before charging or discharging a battery to avoid any potential damage.
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