Combination resistor circuit how to?

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Danny89

Member
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Indian Land
Can someone show me how they got this answer. Please show formulas used and step by step how to solve. Thanks in advance
45c760bd132465120854fb96c49bbab3.jpg


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winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Just expanding on the above two posts. The whole circuit is a distractor. You don't care about the parallel resistors. You don't care about the voltage from X to Z.

You are told that each of the 12 ohm 'loads' is carrying 2 amps. So you know the voltage across a single 12 ohm resistor by Ohm's law: voltage =current * resistance.

Next you know that devices in parallel all see the same voltage. So the voltage across one resistor is the same as the others and your answer.

All of the answers are voltages that you might get figuring the entire circuit, such as the voltage from X to Z or X to Y or 3* the voltage across a single resistor which is not correct at all.

-Jon
 
don_resqcapt19

don_resqcapt19

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Staff member
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Illinois
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retired electrician
I see that is a 6 amp circuit through 24 ohms.
EDIT:
I see they only want the voltage across the 12 ohm loads.
 
kwired

kwired

Electron manager
Location
NE Nebraska
don_resqcapt19 said:
I see that is a 6 amp circuit through 24 ohms.
EDIT:
I see they only want the voltage across the 12 ohm loads.
Click to expand...
I see the question fooled even someone with some experience.:)

Danny89 - trick to answering many of those kinds of institutional geared questions is to make sure you pay attention to details in the question. All they asked for is voltage between two points, but gave you a picture with several other things that are irrelevant to the question, you need to find what it is you are looking for and ignore the rest - it is there to make you think.
 
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ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Consulting Electrical Engineer - Photovoltaic Systems
kwired said:
I see the question fooled even someone with some experience.:)

Danny89 - trick to answering many of those kinds of institutional geared questions is to make sure you pay attention to details in the question. All they asked for is voltage between two points, but gave you a picture with several other things that are irrelevant to the question, you need to find what it is you are looking for and ignore the rest - it is there to make you think.
Click to expand...

One might argue that questions which do that are more valid for testing understanding. The real world never gives you a problem to solve where the only things you see are what relates to the problem.
 
kwired

kwired

Electron manager
Location
NE Nebraska
ggunn said:
One might argue that questions which do that are more valid for testing understanding. The real world never gives you a problem to solve where the only things you see are what relates to the problem.
Click to expand...
I agree, this does help some to set you up for real problem solving, you must learn what is relevant and what is not to the issue you are trying to solve.
 
480sparky

480sparky

Senior Member
Location
Iowegia
ggunn said:
One might argue that questions which do that are more valid for testing understanding. The real world never gives you a problem to solve where the only things you see are what relates to the problem.
Click to expand...

I'd argue the question is designed to make you fail the test, then have to pony up to take it again.
 
kwired

kwired

Electron manager
Location
NE Nebraska
480sparky said:
I'd argue the question is designed to make you fail the test, then have to pony up to take it again.
Click to expand...
If a higher education institution, I don't have a problem with it, it improves the student's problem solving skills if they don't figure it out the first time. If you make it through two or even four years and are still getting stumped by similar questions, maybe this isn't the correct field of study for you.
 
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