Bob F Posted February 9, 2009 Report Share Posted February 9, 2009 The conventional theory of current flow says that current flows: Randomly. Positive to negative. Negative to positive. None of the above. Quote Link to comment Share on other sites More sharing options...
Shropfisher Posted February 10, 2009 Report Share Posted February 10, 2009 Small note, looking at the votes ( after voting ) most have gone for the true flow not the conventional thought. Quote Link to comment Share on other sites More sharing options...
djredrupp Posted February 10, 2009 Report Share Posted February 10, 2009 so whats the right answer? A-level tells me its neg to pos.... but the majority vote says Positive to Negative! which is "conventional thought" ?? Quote Link to comment Share on other sites More sharing options...
Bob F Posted February 10, 2009 Author Report Share Posted February 10, 2009 76% voted + to -. 20% voted - to +. 4% voted randomly. The correct answer is positive to negative for Conventional Flow Theory. Unfortunatlely, there are two theories to describe current flow. The Conventional Theory, commonly used for automotive and marine electrical systems, says that current flows from + to -. Electron Theory states that current flows from - to +. Electron theory is the modern theory that is used in electronics and semiconductors. It is actually the true direction of current flow, and is important when understanding the operation of electronic devices like diodes and transistors. Conventional Theory stems from the early experimenters who at that time did not have the knowledge of atoms and electrons. The automotive inductry still uses conventional theory, partly from history but also because the direction of current flow actually makes no difference to the three measurable units of electricity: voltage, current and resistance. So, now that you are thoroughly confused, it can only get better from here. Quote Link to comment Share on other sites More sharing options...
djredrupp Posted February 10, 2009 Report Share Posted February 10, 2009 summarising... Electron Theory states that current flows from - to + It is actually the true direction of current flow. woop A level physics! Quote Link to comment Share on other sites More sharing options...
gaffa Posted February 10, 2009 Report Share Posted February 10, 2009 Ah the good old Electron Theory .......where electrons are displaced and holes move causing a "current flow" Easiest way to understand it is to think of that good old favourite "executive toy" the swinging balls. If the ball is swung to hit the first ball in the line then the ball at the other end is "Instantly" displaced causing a "hole" to appear for a fraction of a second into which the preceding ball travels thus filling up the space. Efectively we have a flow of holes followed by Balls from one end of the line to the other. Well I never really believed Electron Theory was anything other than a "load of Balls" in the first place Peteg Quote Link to comment Share on other sites More sharing options...
djredrupp Posted February 10, 2009 Report Share Posted February 10, 2009 teachers often use the water analogy.. but that flops at the first hurdle... the easiest one is a tube of marbles..... where as u push one in one end (push being the voltage...), one pops out instantly the other end.... and their movement can be simply shown as the current.... though that is a bit of an uber simplification... Quote Link to comment Share on other sites More sharing options...
gaffa Posted February 10, 2009 Report Share Posted February 10, 2009 There you go Dan I told you it was a load of Balls or Marbles Quote Link to comment Share on other sites More sharing options...
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