# B Charging a capacitor with a battery

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1. Feb 14, 2017

### Cozma Alex

How does it work? I mean I know all the stuff, there is difference in potential and the charges flows, my question is, does the negative terminal of the batteries suck charges or the charges flowing to the negative terminal are flowing because they are pushed by the charges induced on the plate by the other plate connected to the positive terminal? How does charging really work? If it doesn't suck the charges then we should be able to charge a capacitor by just connecting a plate to the positive terminal and the other to the ground, is that right?

Last edited: Feb 14, 2017
2. Feb 14, 2017

### jbriggs444

Does your vacuum cleaner suck or does atmospheric pressure blow into the nozzle because less air than normal is present?

3. Feb 14, 2017

### Cozma Alex

The last

4. Feb 14, 2017

### jbriggs444

What difference does it make, if any?

5. Feb 14, 2017

### Cozma Alex

None, So... the plate connected to the positive terminal charges, it induce an opposite charge on the other plate that now is at higher potential, and then charges flows from here to the negative terminal that is athe 0 potential, is that right? Cos that my analysis of the phenomenon using what you are suggesting, and how can the second plate be at higher potential f it is charged negatively? Actually the potential of it is lower than 0, but i know that charges flows from the plate to the negative terminal, why?

6. Feb 14, 2017

### jbriggs444

The positive plate (the one connected to the positive terminal) now is at a higher potential then the negative plate (the one connected to the negative terminal). Conventional charge has flowed onto the positive plate and off of the negative plate.

The battery forces conventional charge to move against the direction of the potential difference -- from positive to negative, yes.

But the negative terminal is not necessarily at zero potential. Zero potential is arbitrary.

It can't and it won't.
What makes you say this?

Possibly you need to step back and assign a potential to all points in the circuit before you make the connections between battery and capacitor. Then run through what you think happens. Rather than put the zero potential at the negative terminal, why not put zero potential at the mid-point of the battery?