# Unique battery

1. Aug 31, 2008

### casanova2528

can you design a series capacitor and battery set up where one plate of a capacitor in series has an unequal amount of charge ? Feel free to use different dielectrics or any other devices, but the set up must be in series.

2. Sep 1, 2008

### Staff: Mentor

What is the context of your question? Is this for school or for work?

3. Sep 1, 2008

### casanova2528

It's a question I thought about as I working on some dielectric problems. what's with your question??? What if my question was for work or for school...what difference does that make?

4. Sep 1, 2008

### Staff: Mentor

The difference is this isn't a "do my homework for me" forum. We want people to show some effort at answering their own questions (even questions that aren't homework, for that matter).

5. Sep 1, 2008

### casanova2528

Here's my background. I am reviewing my circuits, and I am in the section of dielectrics and capacitors. I've been comparing what happens to the electric field as you insert and take out a dielectric with a constant more than 1 as the battery remains connected. If you do the math, you'll know that the electric field will be the same indicating that the charge on the plates will be the same for a parallel plate capacitor. So, I am wondering if there is any way you can alter the electric field by placing a different amount of charge on each plate as you maintain battery connection using dielectrics.

Trust me...I've done all the math behind all the steps to get to this point. I've compared inserting a conductor and a dielectric...and if you've done the math..you'll see that you will alter the electric field when you insert the conductor due to the change in distance...more charge will flow from battery to the parallel plate. However, Dielectric insertion is different. You can't seem to alter the electric field when the parallel plate capacitors are hooked up to the battery.

I apologize for my rudeness. how can you alter the electric field using dielectrics and anything else while maintaining the battery hook up? The circuit must be in series.

Last edited: Sep 1, 2008
6. Sep 1, 2008

### casanova2528

I'm sorry for being rude, but I had just woken up to the surprise of a quick reply to my question that I've been waiting for. When I discovered my question was answered with another question, I became agitated.. I'm sorry. I need your assistance.

7. Sep 1, 2008

### Staff: Mentor

No worries. I think Russ' explanation helped you to understand how we do things here at the PF.

To the question you are asking - you can charge up a capacitor, and then deposit static charge on one plate to make the amount of charge on the two plates unequal, but I'm not sure that's what you are asking. You'd need a diode in series anyway to make the extra charge not able to leak off. But the excess static charge on the one plate (call it the - plate, so the excess charge is electrons) will have a very weak extra contribution to the electric field in the cap gap -- the field would be terminating on whatever the source was for the excess charge. Maybe you could put a floating plate on the far side of the + cap plate, and suck electrons off and deposit them on the - plate of the cap....

8. Sep 1, 2008

### casanova2528

Even if you have 2 different dielectrics inserted in on capacitor to create a series capacitor system, the charges on the plates seem to be the same when battery remains connected.

9. Sep 2, 2008

### casanova2528

what does a diode do?

10. Sep 2, 2008

### casanova2528

there has to be a better way than to add static charge.

11. Sep 2, 2008

### Staff: Mentor

Just do a quick search at wikipedia.org -- a diode basically blocks current flow in one direction, but allows it (with a small voltage drop) in the other diretion. These are referred to as the reverse and forward directions, respectively.

Well, if you want uneven charge on the two capacitor plates, that would be the main way to do it.

I still honestly have no idea what you are asking for, so it's hard to think of alternatives.