# Series resistors' output voltage

Tags:
1. Mar 26, 2016

### Puglife

In my electrical engineering textbook, in the section with voltage dividers, it says that after you combine two series resistors, then the output voltage can no longer be defined.

It then said that thus the equivalence was made strictly from a voltage source standpoint.

I do not understand why the output voltage would be no longer defined?

2. Mar 26, 2016

### phinds

The statements as you express them make no sense. Please quote it EXACTLY.

3. Mar 26, 2016

### Puglife

"after you combine two series resistors, then the output voltage can no longer be defined, thus the equivalence was made strictly from a voltage source standpoint." was a direct quote, and that's all it said. Their was a picture of a voltage source, and two series resistors right above that statement, but their was not defined output.

I am now assuming that the output is the voltage across resistor 2, because that is the only thing that makes any sense. I was just wondering if their was any like, laws, or insight that I was missing that I didnt understand

4. Mar 26, 2016

### phinds

Still doesn't make sense to me. I'd have to see the exact circuit to which they have applied that statement.

5. Mar 26, 2016

### davenn

agree with phinds .... in particular the

do you see any problem in this voltage divider ?
what do you think the voltage at point B is ?

Dave

6. Mar 27, 2016

### CWatters

Can you scan that page of your book?

I'm wondering if the circuit comprises a battery with internal resistance and a load resistor? In that case if you combine the two resistors into one the node representing the battery terminal (aka output voltage) disappears.

7. Mar 27, 2016

### Staff: Mentor

Since the word "after" is not capitalized, does that mean it isn't the first word in the sentence...? Yes, additional context would help.

8. Mar 27, 2016

### sophiecentaur

Is essential, I think.

9. Mar 27, 2016

### Staff: Mentor

I think it just means that the output voltage of a voltage divider can't be defined anymore after you combine the input resistor and the pull-down resistor in series. Like if you are solving a circuit that has a potentiometer in it or something, and need to combine the two sides of the pot to help you solve for some voltage other than the wiper voltage...