Greeting AAC Family,
The next topic I am delving into is understanding open v. short circuits.
I'll get to the attached problem in a second, but the way I understand it is this. An open circuit is one where no current will be able to flow, so the resistance is infinite. A short is essentially a wire with no resistance. If there is an alternate way to understand this fundamentally  I am all ears!
So, with the attached, I have to find R_t when the a and b terminals are (a) opencircuited, and (b) shortcircuited.
Game plan for (a):
Akin to the "walking from a to b" guidance that @WBahn provided, for an open circuit I realize that no current will flow over a and b, so we can treat the 3 Ohm resistor in parallel with the 4 Ohm resistor, and the 5 Ohm in parallel with the 8 Ohm. That result (~4.79 Ohms) would then be in parallel with the 10 Ohm resistor, and then that result (~3.23 Ohms) would be in series with the 7 Ohm and 8 Ohm resistor, for a grand total of 18.2 Ohms. That answer checks.
Game plan for (b):
For a short circuit I realize that current will flow over a and b and there won't be much resistance, so we can treat the 8 Ohm resistor in parallel with the 4 Ohm resistor, and the 3 Ohm in parallel with the 5 Ohm. That result (~4.535 Ohms) would then be in parallel with the 10 Ohm resistor, and then that result (~3.12 Ohms) would be in series with the 7 Ohm and 8 Ohm resistor, for a grand total of 18.1 Ohms. That answer checks.
What I am not seeing:
Ok, I see part (a) with 3 Ohm  4 Ohm and 5 Ohm  8 Ohm when no current flows from a to b since it's not connected. No question there. But for part (b), I am having a hard time visualizing how 8 Ohm  4 Ohm and 3 Ohm  5 Ohm given that the terminals would now be connected. At first glance, to be honest I thought they would all be in series if the middle wire were connected. Admittedly, my approach for part (b) was "brute force" to match the answer, but I want to understand "why."
Thank you again for your help. Oh, and yes, this is not homework, just to get back into it (selfstudy).
10th
The next topic I am delving into is understanding open v. short circuits.
I'll get to the attached problem in a second, but the way I understand it is this. An open circuit is one where no current will be able to flow, so the resistance is infinite. A short is essentially a wire with no resistance. If there is an alternate way to understand this fundamentally  I am all ears!
So, with the attached, I have to find R_t when the a and b terminals are (a) opencircuited, and (b) shortcircuited.
Game plan for (a):
Akin to the "walking from a to b" guidance that @WBahn provided, for an open circuit I realize that no current will flow over a and b, so we can treat the 3 Ohm resistor in parallel with the 4 Ohm resistor, and the 5 Ohm in parallel with the 8 Ohm. That result (~4.79 Ohms) would then be in parallel with the 10 Ohm resistor, and then that result (~3.23 Ohms) would be in series with the 7 Ohm and 8 Ohm resistor, for a grand total of 18.2 Ohms. That answer checks.
Game plan for (b):
For a short circuit I realize that current will flow over a and b and there won't be much resistance, so we can treat the 8 Ohm resistor in parallel with the 4 Ohm resistor, and the 3 Ohm in parallel with the 5 Ohm. That result (~4.535 Ohms) would then be in parallel with the 10 Ohm resistor, and then that result (~3.12 Ohms) would be in series with the 7 Ohm and 8 Ohm resistor, for a grand total of 18.1 Ohms. That answer checks.
What I am not seeing:
Ok, I see part (a) with 3 Ohm  4 Ohm and 5 Ohm  8 Ohm when no current flows from a to b since it's not connected. No question there. But for part (b), I am having a hard time visualizing how 8 Ohm  4 Ohm and 3 Ohm  5 Ohm given that the terminals would now be connected. At first glance, to be honest I thought they would all be in series if the middle wire were connected. Admittedly, my approach for part (b) was "brute force" to match the answer, but I want to understand "why."
Thank you again for your help. Oh, and yes, this is not homework, just to get back into it (selfstudy).
10th
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