Storing Cookies (See : http://ec.europa.eu/ipg/basics/legal/cookies/index_en.htm ) help us to bring you our services at overunity.com . If you use this website and our services you declare yourself okay with using cookies .More Infos here:
https://overunity.com/5553/privacy-policy/
If you do not agree with storing cookies, please LEAVE this website now. From the 25th of May 2018, every existing user has to accept the GDPR agreement at first login. If a user is unwilling to accept the GDPR, he should email us and request to erase his account. Many thanks for your understanding

User Menu

Custom Search

Author Topic: Can electrons flow in opposite directions on the same wire, see schematic!  (Read 40550 times)

kmarinas86

  • Full Member
  • ***
  • Posts: 156
    • YouTube - kmarinas86's Channel
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #15 on: September 22, 2010, 02:41:51 PM »
I will try to make this as simple as I can.

When you connect to the center of the two batteries, that junction becomes 0-Volts, AKA ground or earth, in respect to the other two poles, the far left pole becomes -1.5V and the far right +1.5V. You should also notice, if you have connected both motors correctly, that the two motors spin in different directions (I think but I may be wrong), this is because the polarity at one end is mirror image to the other. You should also notice that each motor is only receiving 1.5-Volts.

Disconnect the vertical center green wire, then both motors should spin in the same direction, this is because now the far right positive end is 3-Volts, in respect to the far left negative. With that wire disconnected, one motor will speed up if the other one is labored or stalled, very handy for a differential effect in a model car or robot.

That kind of circuit is simply a voltage splitter, very handy for reversible speed control circuits.

How can you have current going out of the positive on one side and current out of the negative in the other? Batteries don't work like that.

What do you think would happen if you had two rectangular circuits, each with a motor and a battery operating, and then decided to connect a little wire between the hot side of the first one and the cold side of the second one? Would one motor reverse direction? I think not. I understand that is not actually the same circuit, but you could take four plates of copper and arranged them like an H like you have in my example and some how build it so you could then rearrange them like H tilted over like in your diagram, then would the motor reverse? Never. Not in a million years.

The ability for the battery on the left to power that motor directly is largely dependent on the size of the conductor relative to your current. If you use very wide conductor plates, it would easy for the opposing currents to be split, but if they were so thin, then it would be more like attaching a meter across with high impedance, and you basically get nothing going through there. Somewhere in between those two situations you would have something like a ground that is 1.5V less than the rest of the circuit.

Your diagram below:

the_big_m_in_ok

  • Hero Member
  • *****
  • Posts: 2087
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #16 on: September 22, 2010, 09:20:41 PM »
... This is not strange, it just may look that way. See the link below of a dual supply from the mains. It's the same thing essentially.
Dual supply diagram
.99
.99 may have a point.  An astable multivibrator using a push-pull inverter can do the same thing as the diodes in the schematic.

http://upload.wikimedia.org/wikipedia/commons/3/39/Astable_multivibrator.png

--Lee

Bulbz

  • Sr. Member
  • ****
  • Posts: 419
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #17 on: September 22, 2010, 09:22:35 PM »
How can you have current going out of the positive on one side and current out of the negative in the other? Batteries don't work like that.

I never said that, I said the junction where the batteries meet act as a ground. I think you misunderstood me.

Get yourself two batteries, and one motor, connect the two batteries in series and connect a wire to the point where the batteries meet (the center). Connect that wire to on side of the motor, then connect the other side of the motor to one of the open ends of the battery assembly. The motor will obviously spin and if you connect it to the other end of the battery assembly, it will spin the opposite direction.

I know that is right, I was taught it in college yonks ago. It is also the configuration that is used in a push-pull amplifier.

kmarinas86

  • Full Member
  • ***
  • Posts: 156
    • YouTube - kmarinas86's Channel
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #18 on: September 23, 2010, 12:36:27 AM »
I never said that, I said the junction where the batteries meet act as a ground. I think you misunderstood me.

Get yourself two batteries, and one motor, connect the two batteries in series and connect a wire to the point where the batteries meet (the center). Connect that wire to on side of the motor, then connect the other side of the motor to one of the open ends of the battery assembly. The motor will obviously spin and if you connect it to the other end of the battery assembly, it will spin the opposite direction.

I know that is right, I was taught it in college yonks ago. It is also the configuration that is used in a push-pull amplifier.

Where is the AC in the diagram?

With batteries, wires, and nothing else, those motors cannot be AC and be made to run properly.

For the motor on the left to run the opposite direction, you're asking the direct current from the other side of the battery to power the motor.

Your diagram:

Bulbz

  • Sr. Member
  • ****
  • Posts: 419
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #19 on: September 23, 2010, 02:30:16 AM »
Where is the AC in the diagram?

With batteries, wires, and nothing else, those motors cannot be AC and be made to run properly.

For the motor on the left to run the opposite direction, you're asking the direct current from the other side of the battery to power the motor.

Your diagram:

AC ?, there is no AC and the motors aren't either. I was simply trying to describe as simply as I can that current doesn't run in both directions in the center wire. The circuit is simply a voltage divider !

[me]Bangs head against wall[/me]

fritznien

  • Sr. Member
  • ****
  • Posts: 294
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #20 on: September 23, 2010, 02:51:16 AM »
assume both batteries are the same and both motors are the same.
there will be no voltage between the battery junction and the motor junction
the motors act as a voltage divider, the batteries are center tapped.
without voltage there can be no currant in the cross link.
no indication on the diagram of motor polarity so no way to say what direction they turn but the polarity of the applied voltage on the motors will not change with or without the cross link.
fritznien

kmarinas86

  • Full Member
  • ***
  • Posts: 156
    • YouTube - kmarinas86's Channel
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #21 on: September 23, 2010, 03:18:01 AM »
I will simply quote what I said earlier:

Quote from: kmarinas86
The ability for the battery on the left to power that motor directly is largely dependent on the size of the conductor relative to your current. If you use very wide conductor plates, it would easy for the opposing currents to be split, but if they were so thin, then it would be more like attaching a meter across with high impedance, and you basically get nothing going through there. Somewhere in between those two situations you would have something like a ground that is 1.5V less than the rest of the circuit.

kmarinas86

  • Full Member
  • ***
  • Posts: 156
    • YouTube - kmarinas86's Channel
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #22 on: September 23, 2010, 03:19:46 AM »
the polarity of the applied voltage on the motors will not change with or without the cross link.
fritznien

Exactly.

exnihiloest

  • Hero Member
  • *****
  • Posts: 715
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #23 on: September 23, 2010, 03:54:12 PM »
AC ?, there is no AC and the motors aren't either. I was simply trying to describe as simply as I can that current doesn't run in both directions in the center wire. The circuit is simply a voltage divider !

Not at all.
As the motors do not draw the same current at each moment of time during each turn, due to the switching connections and the variable coupling between coils and magnets, it is obvious that there is an AC current (with a frequency depending on the number of turns/s and on the number of coils, + harmonics).




Bulbz

  • Sr. Member
  • ****
  • Posts: 419
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #24 on: September 23, 2010, 07:15:25 PM »
Not at all.
As the motors do not draw the same current at each moment of time during each turn, due to the switching connections and the variable coupling between coils and magnets, it is obvious that there is an AC current (with a frequency depending on the number of turns/s and on the number of coils, + harmonics).

What if you swapped the motors for light bulbs, there shouldn't be any AC fluctuation and those bulbs will still light up.

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #25 on: September 23, 2010, 11:50:04 PM »
Not at all.
As the motors do not draw the same current at each moment of time during each turn, due to the switching connections and the variable coupling between coils and magnets, it is obvious that there is an AC current (with a frequency depending on the number of turns/s and on the number of coils, + harmonics).

Yes this is true, however this is not the question of the topic. The question is not whether a current can flow in the common (because I have shown that it can under certain conditions), but whether it has to based on the notion that it appears to be the path of least resistance.

The issue has very little to do with which path has the least resistance, and quite a lot to do with Kirchoff's current law, and mesh currents. The only thing that determines if there is current in the common lead is if the loads are unbalanced or balanced. With a perfectly balanced load, the common lead can be removed and the circuit will operate the same. There will be no potential at the common node where the loads connect, and therefore no current in the common leg.

.99

angryScientist

  • Full Member
  • ***
  • Posts: 223
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #26 on: September 23, 2010, 11:59:49 PM »
With high frequency ac the current can flow in two directions at the same time. It's a well known fact in some circles. I'm thinking a transmission line that is long (longer than 1/2 wave length) or if the frequency is very high (since I just read a book on it). In one part of the wire the current is going one way and in another part the current is going another.

What really puzzles me is when you have a transmission line or antenna and the wave is reflected off the end and it comes back and is supper imposed over the next wave traveling in the opposite direction. At that instant it there would be no voltage on the line and no magnetic field surrounding it.

How in the world does the wave know to continue?! There is no difference in potential. It's like it just bleeps out of existence and then comes right back. There wouldn't be any momentum because the electrons would be standing still.

I still don't get it. It seems kind of freaky to me!

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #27 on: September 24, 2010, 01:05:07 AM »
If the frequency is high enough, then you could have an AC current on the skin of the wire and a DC current in the entire cross-section, including the skin.

It still comes down to the net potential across the wire, and for one half of the AC cycle the AC and DC currents will add, and in the other half they will subtract. The two currents are not mutually exclusive of one another (i.e. electrons never pass each other going opposite directions).

So there are not two currents running in opposite directions. The current will run either one way or the other, depending on the net potential across the ends of the wire at any instant of time.

Take as an example two current sources connected to a wire: one sources 10mA DC, and the other sources 1mA AC sine-wave at 500MHz. Now if you utilize your 10GHz Hall effect current probe (good luck finding one) to measure the current in that single wire, you will see a current fluctuating between 9mA and 11mA at a sine frequency of 500MHz.

.99

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #28 on: September 24, 2010, 02:31:51 AM »
What really puzzles me is when you have a transmission line or antenna and the wave is reflected off the end and it comes back and is supper imposed over the next wave traveling in the opposite direction. At that instant it there would be no voltage on the line and no magnetic field surrounding it.

That depends on whether the reflection is the same (open circuit) or opposite (short circuit) polarity as the incoming wave or pulse.

Quote
How in the world does the wave know to continue?! There is no difference in potential. It's like it just bleeps out of existence and then comes right back. There wouldn't be any momentum because the electrons would be standing still.

I still don't get it. It seems kind of freaky to me!

Transmission lines (TL) exhibit a local effect. A pulse sufficiently short to be small in comparison to the length of the transmission line will propagate along at some fraction of c, but until that pulse reaches the end, the "end" is not even aware of the pulse. If the end is not terminated in the characteristic Z of the TL, there will be a reflection, and if there are sequential pulses, the reflected pulse will intersect the next advancing one. What happens there is the same as what happens on a single wire; the two currents mesh. Either they add or subtract locally. They continue to propagate past each other because the TL is made up of a series of storage elements, and the energy in them can not be destroyed.

.99

angryScientist

  • Full Member
  • ***
  • Posts: 223
Re: Can electrons flow in opposite directions on the same wire, see schematic!
« Reply #29 on: September 24, 2010, 04:36:45 AM »
First half, poignant. It's what I've read. I like. For sure.

Second, I'm still not seeing it. If they add together and nullify each other then where is the energy. Which dimension is the energy contained in? Not in the electric or magnetic or even mass.

I still don't comprehend...