Electronics > Beginners

Conventional current vs electron current - elements in different order

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IanB:

--- Quote from: nForce on October 19, 2019, 03:04:48 pm ---Oh, I get it now. The problem I made is I changed the input and output of any kind of circuit. I should just switch the polarity of the battery at the INPUT. But why do we have then reverse voltage protective devices like a diode, if there is no matter in which direction the current flows?

--- End quote ---

Because it matters a lot which direction the current flows. Electronic devices are designed to work with a certain polarity of supply. If you change the polarity will not work and may be damaged.

When you change the current model from conventional current to electron current you may not make any physical changes to the circuit. You may only change the equations you use to model the circuit in your mind and on paper.

It should be clear to you that what you think in your mind makes no difference to how things actually work. It doesn't matter whether I think my car works on internal combustion or whether I think it works with magic pixies. My car continues to work the same either way.

Nerull:

--- Quote from: nForce on October 19, 2019, 03:04:48 pm ---Oh, I get it now. The problem I made is I changed the input and output of any kind of circuit. I should just switch the polarity of the battery at the INPUT. But why do we have then reverse voltage protective devices like a diode, if there is no matter in which direction the current flows?

--- End quote ---

AC was perhaps a bad example, since it involves an "actual" change in current direction and not just a mathematical one.

Conventional current has positive charges moving from positive to negative, while electron current has negative charges moving from negative to positive. These are equivalent - both result in a net movement of charge from positive to negative. The direction of *charge* remains the same. When working at a high level, you only care about charge and not the actual charge carriers. It could be electrons, it could be positive ions, it could be a mix of both. It makes no difference. It is equivalent to consider a diode allowing positive charge to move from anode to cathode as it is to consider it allowing negative charge to move from cathode to anode. Unless you're working at the solid state physics level, you don't have to care what the actual charge carriers are doing or what they even are.

Consider the water analogy and a one way valve. You could say a one way valve opens when the pressure on high side is more positive than the pressure on the low side. You could also say that a one way valve opens when the pressure on the low side is lower than the pressure on the high side. These are two ways of saying the same thing. Nothing about the valve or the actual flow of water has changed, just  where you decide to stick your frame of reference to do the math.

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