Understanding Ground Potential: My Experience with a Volt Meter

[atom888]

Hi everyone,

I just bought a volt meter today to play around. To my understanding about electricity and all, I've always been taught that potentials have references. We always reference ground as zero potential. I put the volt pins between a small battery and it reads about 1.6 volts, so I thought if ground is zero potential, then it should read some voltages across the battery and ground. However, the meter reads zero. What is my misunderstanding about ground term? Is ground literally ground and have 0 potential? lol

 

[Redbelly98]

Yes, potentials have references. For the voltmeter, the reference is whatever is connected to the "com" terminal (usually through a black wire). The meter reading is then the voltage of whatever is connected to the other wire (usually colored red), with respect to this reference.

You need to connect one wire to the battery's PLUS terminal, and the other wire to the battery's MINUS terminal.

Make sure the meter is set to read DC Volts. If it is set to read AC Volts, it will read zero for a battery.

 

[atom888]

Yes, potentials have references. For the voltmeter, the reference is whatever is connected to the "com" terminal (usually through a black wire). The meter reading is then the voltage of whatever is connected to the other wire (usually colored red), with respect to this reference.

You need to connect one wire to the battery's PLUS terminal, and the other wire to the battery's MINUS terminal.

Make sure the meter is set to read DC Volts. If it is set to read AC Volts, it will read zero for a battery.

Thx for the tip. What puzzle me is that when you touch a wire and you standing on the ground, you'll get shock. However, when I check the wire and ground using the volt meter, it reads zero.

 

[Redbelly98]

I am not sure what wire you are talking about, I hope this isn't some dangerous live exposed wire ... is it?

It may be that the wire has an AC voltage, and your meter was set to read DC volts.

 

[atom888]

Thx for the concern Red, I think I still want to live. lol It seems like I have a misunderstanding between a charged object and potential. You can get shock touching a charged object, but there isn't necessary a potential in between the charged and neutral object if measure by a volt meter.

 

[Dozent100]

No! you discharge the potential, that was likely between your hand and Ground. I assume you are referring to the Static Shock those of us who have lived up north. As we walk across carpet, we build up a static charge with a high voltage, Due to the stripping of electrons from the soles of your shoes. Should you measure the potential between your hand and ground you might be surprised at how high the voltage is. Should you manage to measure the current between your hand and ground, you would need a very fast ammeter!