What is infinite resistance?

Thread Starter

Gdrumm

Joined Aug 29, 2008
684
I'm trying to solve a series circuit question from my DC Circuits class homework, and I can't seem to recall what infinate resistance means.

Here is the info I have on the circuit.
E=40v, R1=5ohms, R2=10ohms, R3= Infinate ohms.

I see the answer in the back of the book, but I don't know how they got it.

I'm solving for E Total, I Total, R Total, and P Total.

I'm guessing that infinate resistance means there is a short?
Thanks, Gary
 

KL7AJ

Joined Nov 4, 2008
2,229
I'm trying to solve a series circuit question from my DC Circuits class homework, and I can't seem to recall what infinate resistance means.

Here is the info I have on the circuit.
E=40v, R1=5ohms, R2=10ohms, R3= Infinate ohms.

I see the answer in the back of the book, but I don't know how they got it.

I'm solving for E Total, I Total, R Total, and P Total.

I'm guessing that infinate resistance means there is a short?
Thanks, Gary
Nope...infinite resistance means the component (resistor) does not exist. You may safely remove it from your schematic with no danger of punishment
 

Thread Starter

Gdrumm

Joined Aug 29, 2008
684
Thanks,
But I'm still curious, because in the answer section of my workbook, it shows Total I=0 amps, meaning that R3 in effect neutralized R1 and R2.

So, does this look accurate?
ET = 40v
IT = 0A
RT = 00 ohms
PT = 0 watts

What does "fail open" mean?
I found that on this site, Vol 1, Chapter 5/7.
It implies that a resistor might "fail open", increasing it to near infinate levels.
Thanks, Gary
 
Last edited:

mik3

Joined Feb 4, 2008
4,843
If the resistors are connected in series then no current will flow due to the infinite resistance (open circuit).

if the resistors are connected in parallel then current will flow only through R1 and R2.
 

thingmaker3

Joined May 16, 2005
5,083
I=E/R, so as R increases, I diminishes. As R increases without bound, I approaches zero. Once R is a few zillion yotta-Ohms, I is a few zillionths of a yocto-Ampere.
 

blhoward

Joined Feb 4, 2009
5
I'm trying to solve a series circuit question from my DC Circuits class homework, and I can't seem to recall what infinate resistance means.

Here is the info I have on the circuit.
E=40v, R1=5ohms, R2=10ohms, R3= Infinate ohms.

I see the answer in the back of the book, but I don't know how they got it.

I'm solving for E Total, I Total, R Total, and P Total.

I'm guessing that infinate resistance means there is a short?
Thanks, Gary
Infinite resistance is open circuit (burnt resistor in real life) no current will flow, zero ohms is short circuit.
Lets not confuse.
Brian
 
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