# Voltage drop in Capacitors and Lightbulbs

#### kkroo

The batteries in this cicuit create a total voltage difference of 6 volts across the circuit.
Assume A is 6 vols in each circuit,
Record the voltage of the lettered locations at the time when the circuit is first connected, and later when it is fully charged

Note: bulbs below are identical
PHP:
       |------A (Bulb)--B---(Bulb)----C--| |--D--|
|                                         |
---                                        |
-                                         |
|                                         |
------------------------------------------
PHP:
       |------A--| |--B---(Bulb)--C---(Bulb)---D--| |--E--|
|                                                  |
---                                                 |
-                                                  |
|                                                  |
----------------------------------------------------
Any ideas?

Thanks

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#### tiny-tim

Science Advisor
Homework Helper
Welcome to PF!

Hi kkroo! Welcome to PF!

Show us what you've tried, and where you're stuck, and then we'll know how to help!

#### kkroo

Hello,

I know that the Kirchhoff’s loop rule says the sum of the potential changes in the circuit must be zero. I also know that when the capacitor is fully charged, there is no potential difference bwtween the bubls because they dont shine. Here is what I think so far, but I have no idea if its correct.

Charging:
PHP:
       |------6 (Bulb)--3---(Bulb)----0--| |--0--|
|                                         |
---                                        |
-                                         |
|                                         |
------------------------------------------
Charging:

PHP:
       |------6--| |--6---(Bulb)--3---(Bulb)---0--| |--0--|
|                                                  |
---                                                 |
-                                                  |
|                                                  |
----------------------------------------------------
Charged:
PHP:
       |------6 (Bulb)--6---(Bulb)----6--| |--0--|
|                                         |
---                                        |
-                                         |
|                                         |
------------------------------------------
Charging:
( aim especially stuck on this one, I know the opposite capacitor plates should have the same charge, but I know there cant be a potential difference between the bulbs.
PHP:
       |------6--| |--0---(Bulb)--0---(Bulb)---6--| |--0--|
|                                                  |
---                                                 |
-                                                  |
|                                                  |
----------------------------------------------------
Any ideas? Please help as soon as you can, this is due in an hour and a half.

Thanks

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