Is There a Problem with Two Grounds in This Simple Circuit?

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Discussion Overview

The discussion revolves around a circuit diagram featuring two grounds and the implications of voltage measurements at various points in the circuit. Participants explore the potential issues related to voltage drops across components and the interpretation of ground connections.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Homework-related

Main Points Raised

  • One participant questions whether the presence of two grounds in the circuit indicates a problem, suggesting that more voltage may need to drop across the resistor R.
  • Another participant challenges the voltage readings provided, stating that the voltage at point "a" is the output of a 10V power supply, implying that the initial claim of 16V is incorrect.
  • A later reply suggests that the circuit is labelled incorrectly, pointing out inconsistencies in the voltage readings and asking for the source of the circuit diagram.
  • One participant explains that the voltage at point "a" should be 10V and at point "b" should be 20V, leading to a voltage drop of 10V across the resistor, contradicting earlier claims of a 4V drop.
  • Another participant mentions that the voltage readings depend on the placement of the negative probe of the measuring device, indicating that measurement context is crucial.

Areas of Agreement / Disagreement

Participants express differing views on the voltage readings and the implications of the circuit's design. There is no consensus on whether the circuit is correctly labelled or whether the voltage drops are accurately represented.

Contextual Notes

Participants reference specific voltage measurements and the configuration of the circuit, but the discussion does not resolve the inconsistencies in these measurements or the assumptions made about the circuit's design.

Who May Find This Useful

Individuals interested in circuit analysis, voltage measurement techniques, and those studying electrical engineering concepts may find this discussion relevant.

PainterGuy
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hello everyone,:wink:

can someone please help me with the problem in the circuit on the following link:-
http://img848.imageshack.us/img848/1108/groundproblem.jpg

there are two grounds (0V) (which means they can be connected to complete the circuit). don't you think there is problem with the circuit?

going counter clockwise: the voltage at "b" is 20V, at "a" 16V, and after traversing the E1=10V, the remaining voltage is 6V. do you get my what i am trying to say?:rolleyes: perhaps, more volts need to drop across the resistor R.

i am very grateful for any help you can give me.

cheers
 
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painterguy said:
hello everyone,:wink:

can someone please help me with the problem in the circuit on the following link:-
http://img848.imageshack.us/img848/1108/groundproblem.jpg

there are two grounds (0V) (which means they can be connected to complete the circuit). don't you think there is problem with the circuit?

going counter clockwise: the voltage at "b" is 20V, at "a" 16V, and after traversing the E1=10V, the remaining voltage is 6V. do you get my what i am trying to say?:rolleyes: perhaps, more volts need to drop across the resistor R.

i am very grateful for any help you can give me.

cheers

The voltage at "a" is the 10V power supply's output voltage, so there is more than 4V across the resistor. Where did you get 16V?

Is this a schoolwork question? Self study?
 
painterguy said:
hello everyone,:wink:

can someone please help me with the problem in the circuit on the following link:-
http://img848.imageshack.us/img848/1108/groundproblem.jpg

there are two grounds (0V) (which means they can be connected to complete the circuit). don't you think there is problem with the circuit?

going counter clockwise: the voltage at "b" is 20V, at "a" 16V, and after traversing the E1=10V, the remaining voltage is 6V. do you get my what i am trying to say?:rolleyes: perhaps, more volts need to drop across the resistor R.

i am very grateful for any help you can give me.

cheers

berkeman said:
The voltage at "a" is the 10V power supply's output voltage, so there is more than 4V across the resistor. Where did you get 16V?

Is this a schoolwork question? Self study?

hi berkeman,:smile:

you can say it's self-study to improve understanding. in the original i also say that there has to be more volts across the resistors. because if you start traversing the circuit from point "c" counter clockwise you get 16V at "a". do this make sense? please tell me. many thanks for your help.

cheers
 
painterguy said:
hi berkeman,:smile:

you can say it's self-study to improve understanding.

Even if for self-study, you should be posting questions like this in the HH/Intro Physics forum, and not in the General Physics forum.

painterguy said:
in the original i also say that there has to be more volts across the resistors. because if you start traversing the circuit from point "c" counter clockwise you get 16V at "a". do this make sense? please tell me. many thanks for your help.

Then the "circuit" is labelled incorrectly. The "4V" drawn at the resistor is inconsistent with the rest of the circuit. Where did the circuit come from?
 
berkeman said:
Even if for self-study, you should be posting questions like this in the HH/Intro Physics forum, and not in the General Physics forum.

sorry,:shy: i am new to this forum. will learn these things soon. where to post what.

berkeman said:
Then the "circuit" is labelled incorrectly. The "4V" drawn at the resistor is inconsistent with the rest of the circuit. Where did the circuit come from?

just made it up by using a circuit saw in a book. please tell me if the volts drawn at the resistor have been fixed then the grounds are thought to be connected to complete the circuit because both are at 0V. many thanks for teaching me this stuff.

cheers
 
Get a bit of freeware called yenka and draw the circuits and it'll test them for you
 
painterguy said:
just made it up by using a circuit saw in a book. please tell me if the volts drawn at the resistor have been fixed then the grounds are thought to be connected to complete the circuit because both are at 0V.

As drawn, the circuit grounds are the same (hence connected), and the common practice is to call the voltage at the ground symbols 0V.

As drawn (forget the "4V" text), the voltage at "a" is 10V, and the voltage at "b" is 20V, so the voltage drop across the resistor is 10V.
 
many thanks berkeman. you have really helped me. hope you will keep helping me in future.

cheers
 
painterguy said:
hello everyone,:wink:

can someone please help me with the problem in the circuit on the following link:-
http://img848.imageshack.us/img848/1108/groundproblem.jpg

there are two grounds (0V) (which means they can be connected to complete the circuit). don't you think there is problem with the circuit?

going counter clockwise: the voltage at "b" is 20V, at "a" 16V, and after traversing the E1=10V, the remaining voltage is 6V. do you get my what i am trying to say?:rolleyes: perhaps, more volts need to drop across the resistor R.

i am very grateful for any help you can give me.

cheers

4V in the resistor R is wrong.
Assuming you are taking measurement with a meter where the negative probe is at the ground.
Voltage at point 'a' is 10V (same as E1)
Voltage at point 'b' is 20V (same as E2 or E1+volts in R)
Voltage at point 'c' is 0V (ground)
Now if you move the probes between points 'a' and 'b', which is voltage in R, meter will read 10V [20-10=10V] not 4V.

You see it all depends on where you place the negative probe of the meter.
 
  • #10
many thanks Neanderthal00 for the analysis.

cheers
 

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