In the electronics tutorials I read that negative electrons moving from atom to atom as part of the electronic current in a wire. However, other tutorials state that it is the positive electrons that move towards the negative in a circuit. This seems totally contradictory to me. Can someone please clarify this?
Thank You.
An electron has a negative charge. But when Ben Franklin started describing electricity and how current flows, that wasn’t known. So it became the convention to speak of current as if the physical charge carriers (now known as electrons) moved from positive to negative potentials. Latter we came to know that the actual movement of electrons is the opposite. But nobody wanted to change that many years of thinking.
However you can think of the electron moving from atom to atom in another way. If an electron leaves a neutral atom, it leaves behind a positively charged ion. In a flowing current a different electron will soon be bound to that ion, to “fill the hole” left by the 1’st electron. So if electrons move in 1 direction, a flow of “holes” can be thought of as moving in the opposite direction. And a flow of “holes” obeys all the laws that electrons do (as is obvious) and conform to the many years of prior thinking. So that is the accepted manner in which electricity flows, call “conventional flow” (or “conventional current”). But it’s really the holes that are “flowing” in that direction, not the electrons.
Only in antimatter are electrons charged positively. Then they aren’t electrons, but positrons.
Your response was helpful and makes sense so thank you.
So, at this link: https://learn.sparkfun.com/tutorials/what-is-a-circuit, under the sub heading labeled, “The Simplest Circuit”, it shows a diagram. Essentially, it shows a circuit w/ the positive side of the battery connected to a resistor that is connected to an L.E.D. diode, that is connected to the negative side of the battery.
So, shouldn’t the resistor be on the other side of the L.E.D diode if it is to resist the flow of electrons from the negative side to the positive side protecting the L.E.D from too much flow?
Thank You.
Illumna I enjoy your question. I am self taught from books back in the 60’s. My mental logic favors electron movement which I thought was confirmed by solid-state circuits. To make things more interesting I believe an Oscillator demonstrates electron “wiggle” and no flow at all. With either logic, current/hole or electron the basic math still fits. :dance:
Christopher
In a word ... nope. :mrgreen:illumna:
So, shouldn’t the resistor be on the other side of the L.E.D diode if it is to resist the flow of electrons from the negative side to the positive side protecting the L.E.D from too much flow?
Waaaaay back in the mid-1800s a smart Prussian physicist named Gustav Kirchhoff formulated a couple of “laws” that pretty much define the basics of circuit theory. If you want a detailed answer to your question, you’ll need to understand them.
http://en.wikipedia.org/wiki/Kirchhoff%27s_circuit_laws
But to try to simplify, imagine the flow of current is like the flow of water in a pipe. A small diameter pipe will restrict the flow of water (think resistor) more than a large pipe will.
Now imagine a loop of piping that goes from a pump (think voltage source) through some pipes to the small pipe and then to a bucket (think ground), that the pump draws it’s water from. You’ve got a piping/pumping loop. The pump pushes water through the pipes back to it’s bucket, where it picks up the same water and re-pumps it. The flow rate (think current) is determined (in this case because we have an uber strong pump) by the ability to force water though the most restrictive orifice/pipe.
Now put a 1 way valve (think diode) in the piping loop. Then the amount of water flowed through both the small pipe (and all other piping) and valve will be restricted by the smallest pipe in the loop, no matter where it is. If the valve presents no restriction, the small pipe will … and so limit the amount of water flowed anywhere in the pipe loop in any 1 second. Afterall the exact same water flowing through the small pipe flows through the valve and every other section of piping. This is the important concept !
Now if the valve stops the current from flowing (in the “opposite” direction), then … well the flow is zero and there’s really no need to further restrict the current flowed. The diameter of the piping is a “who cares”.
So a resistor will restrict the amount of current flowing … assuming the diode lets any flow … no matter where in the circuit the resistor is.
Thank you everyone for your helpful responses.