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I feel like this is an extremely stupid question, but I am not from electronics! In diagrams, they use conventional current. If I were to make this circuit in real life connecting battery + with diode + with lightbulb +, does this mean electrons flow through the lightbulb first then the diode?

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Niteesh Shanbog
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zenarthra
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  • Conventional current direction is directly opposite to electron current direction. – jonk Oct 26 '18 at 03:28
  • So to create this circuit in real life, i would connect the negative of battery to negative of diode since the electrons flow from -terminal of battery? – zenarthra Oct 26 '18 at 03:40
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    At this level, just pay attention to the flow of current and don't confuse yourself with electrons. *Conventional* current flows through a diode in the direction of the arrow, so the circuit you've drawn on the left will conduct. – TimWescott Oct 26 '18 at 03:45
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    @zenarthra Read [this NASA page on Ben Franklin](https://www-spof.gsfc.nasa.gov/Education/woppos.html) to get an idea why we are today "stuck" using conventional current notation. That may help. Either way, it's just about being consistent. You could decide you want to always "work upstream" and think in terms of electron flow. But then no one else would understand you nearly as well. So it is better if you just go with the flow (bad pun, I know.) – jonk Oct 26 '18 at 04:16
  • Related: [Which way to draw diode in a circuit diagram](https://electronics.stackexchange.com/q/31825/6334). – The Photon Oct 26 '18 at 05:30
  • Also: [What exactly does a diode do?](https://electronics.stackexchange.com/q/52437/6334) – The Photon Oct 26 '18 at 05:30
  • In the back of your mind, file away the fact that electrons flow in the opposite direction as conventional current. And then move on. Never think about it again when studying circuits. Maybe if you study battery chemistry in detail, you may want to revive that bit of information. Or if you study detailed chemistry of electronic devices (like how do transistors and diodes work in detail, inside the device). Otherwise, just remember that current flows from positive to negative. Diodes are arrows that point the way. – user57037 Oct 26 '18 at 05:50

1 Answers1

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Electrons don't flow 'first' through one thing and then the other in a series circuit.

Imagine a bicycle chain, passing round the pedal gear (the battery) and the rear wheel gear (the bulb), with the long straight free sections the wires. Now turn the pedals. The whole chain moves.

This is a limited model, in the sense that some models are useful, but let each link of the chain represent a certain amount of charge. The same charge flows round the circuit at all times. It's given energy by the battery, and gives up energy to the bulb.

The charge per link could be negative (a certain number of electrons) or positive (a deficit in the number of electrons). In our 'conventional current' circuit theory world model, we choose to represent the motion of positive charge, and define our current to move in the direction of the chain. This is just as good a convention as the other one, and works for everybody as long as they are all consistent.

When we get down and dirty with trying to build semiconductors, we find that both positive and negative charges move. So it doesn't matter which convention we pick, neither one is 'more useful', we still need to account for both charges moving in both directions.

Neil_UK
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