moshrom said:
40A. Which means I5=40A, I4=10A, I3=40A, and I6=50A.
I think I knew that before. I'm mainly having trouble grasping the voltages.
There's something you mentioned before that makes me sort of leery. You said,
In a pathway, Voltage in = Voltage out
That's not the way I would phrase it. Voltages don't "flow" through a pathway. Voltage (aka electric potential) simply exists across different places in the circuit.
Saying that voltage goes in or out (or "flows") doesn't make much sense. Imagine a hill of height
h. Asking a question such as "how much potential energy per unit mass flows down the hill?" doesn't make any sense. The potential energy per unit mass (from the top to the bottom of the hill) is simply
gh. It doesn't flow anywhere. It just is.
[btw, voltage can sometimes be thought of as
potential energy per unit charge.]
Across each resistor there is a "voltage drop." There is 0 voltage drop across wires. If two resistors are in series, you can add the voltage drops together to find the voltage difference from the top of the top resistor to the bottom of the bottom resistor.
If two resistors are in parallel (sharing common nodes at their ends) the voltage drops must be equal!
If you add up all the voltage drops in a loop, such that the loop starts and ends in the same place, all the voltages in the loop must add up to zero (you need to consider + and - signs when you go through the loop).
Imagine a house that has an attic, a main floor and a basement. In the basement there is a ladder that you can use to climb up to get outside through a window. From the outside, there is a fire escape that you can use to climb up to an attic window.
Suppose you start in the attic and go down the stairs to the main floor, then go down another set of stairs to the basement, then up the basement ladder to outside, then up the fire escape back into the attic. You end up with the same potential energy you had when you started. There are many things that can be said about this situation, but a couple of them are:
Potential drop of the attic stairs + potential drop of the basement stairs = potential drop of basement ladder + potential drop of fire escape
which is also equal to the potential difference between the attic and the basement.
In terms of adding everything up in a loop, you could say:
- (Potential drop of the attic stairs)
- (potential drop of the basement stairs)
+ (potential drop of basement ladder)
+ (potential drop of fire escape)
= 0
