resistor across voltage source

Discussion in 'General Electronics Chat' started by sharanbr123, Oct 14, 2014.

Sep 29, 2014
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I have a question on current flow across a resistor connected to a voltage source.
We know that current is drawn by the load conneced to the voltage effectively by supplying electrons from negative terminal of the voltage source. The question is does anything gets sinked back to the positive terminal of the voltag source. I am assuming that all the current basically gets dissipated by the resistor.

Can anyone comment?

Feb 17, 2009
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3. crutschow Expert

Mar 14, 2008
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The energy is dissipated in the resistor by the moving electrons but the electrons are unaffected. You can't cause an electron to disappear expect perhaps in a large particle accelerator.

Sep 29, 2014
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It does make sense what you are saying but what does it mean when you charge your power source (like battery) after day long use.

5. alfacliff Well-Known Member

Dec 13, 2013
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it means that you reverse the electrochemical reaction in the battery that supplies electrons.

Sep 29, 2014
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Thanks. Probably one last question. What happens when an element like LED is connected.
Would the charge flow back to the battery or there is loss somewhere in the system?

7. alfacliff Well-Known Member

Dec 13, 2013
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an led properly connected would draw current from the battery. that would use up the charge.

8. wayneh Expert

Sep 9, 2010
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Electrons are conserved and not lost. They flow from source to sink but are not dissipated, like heat or light for instance.

Sep 29, 2014
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I am opening this thread. If eletrons are not lost then in case of HW circuits which are battery operated, why not connect all sink points back to negative terminal of battery. I am assuming that normally, the sink points go to ground and get dissipated. This way, we will never lose any charge.

10. wayneh Expert

Sep 9, 2010
12,155
3,061
What's a HW circuit?
In a battery operated circuit, that's exactly what happens. The battery drives current from its positive pole back to the negative pole. The circuitry is the path that allows this to happen. No circuit, no current flow.
I may not understand your question. The term "ground" is used in many ambiguous ways. In a battery circuit, "ground" usually refers to the negative pole. In household wiring, "ground" really does mean earth ground.

Note that a battery drives current from its positive pole to its negative pole. No current will low if the positive pole of the battery is touched to earth ground, since there is no complete circuit to return current to the negative pole.

Sep 29, 2014
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basically, I meant a circuit that is implementing a function such as in a cell phone etc. just as an example

Circuit is indeed complete but my intuition tells me that part of the current drains into ground and not into the negative terminal of battery.
And this seems to be the reason why battery eventually dies.

12. wayneh Expert

Sep 9, 2010
12,155
3,061
That's not really right. A battery contains chemical energy that is dissipated as current flows from positive back to negative. That current flow ultimately dissipates as heat within the circuit, light from the display, radio energy from the transmitters and so on. No electrical connection to the outside world is required for that energy to dissipate. Once it is gone, the battery's stored chemical energy is spent. The same thing would happen with a battery in space - with no ground anywhere in sight.