(Note: This is a revised post, the previous one was rather confusing and I feel the need to improve it)
Many year agos, the flow of current in a circuit was agreed to flow from the positive terminal of a cell to the negative terminal of a cell. This is what we consider to be Conventional Current. Now, in theory, this doesn’t actually make much sense considering that negatively-charged electrons would be attracted to the positively-charged terminal, not repelled (As is suggested). However, in the past, the positive terminal, negative terminal and current of a cell went by other names when being considered in the context of a circuit. The positive terminal was known as the ‘Surplus’, the negative as the ‘Deficiency’ and charge as ‘Excess’. If we consider this alongside Conventional Current it begins to make some sense. Excess flows from the Surplus to Deficiency which, in other words, takes the ‘extra’ charge from the postive terminal (Where it is plentiful) to the negative terminal (Where it is lacking).
Consider it like this. Imagine a simple train track with just one station and track that loops from end of the platform to the other. Assuming that conventional current is present, the train sets off west of the platform (Postive end) where it then completes the loop back on the eastern end (Negative end) of the train station. It would then continue to do this for as long as a source of energy is supplied to the train (I hope that is a better example than the last time I tried).
Now, since conventional current was theorised, a more accurate theory for the flow of current has been put forward. Electron Flow is the flow of current from the negative terminal to the positive terminal which, when considering the negative charge current has, makes more sense with the negative terminal repelling current and the positive terminal attracting it.
Again, consider the train analogy. Instead of the train moving from the western end (Postive) it moves from the eastern end (Negative) where it arrives at the western end. This, again, carries on as long as a source of energy is provided.
Despite Electron Flow being a better way of explaining the way in which current flows around a circuit, Conventional current is the one widely used. This is due to previous rules being based upon Conventional Current and to change it would create a great deal of unnecessary confusion amongst old and new scientists. You can use either Electron Flow or Conventional current when considering circuits however, generally, Conventional Current is used more often.
- Conventional Current – The flow of current from the postive terminal to the negative terminal.
- Electron Flow – The flow of current from the negative terminal to the postive terminal.
- You can consider either CC or EF so long as you’re consistent but CC is used more often.
It’s been a while since I’ve published a post about Physics. I shall endeavour to post more Physics based posts as well as more History ones. If you have any thoughts or questions please leave them in the comments.