# Charge of electron in AC/DC circuit part II

This is a conversation that came from a previous question, but brought to birth a new question:

http://physics.stackexchange.com/questions/269703/charge-of-electron-in-ac-dc-circuit?noredirect=1#comment601870_269703

" They pick up energy from the electric field which passes through the wire between the terminals. It accelerates the electrons, and they release this energy when they collide with something. " - This part right here is interesting. This may have been explained to me before, but I've never heard it put that way. "" electric field which passes through the wire between the terminals "" what are you trying to say. That once the switch has been turned " on " or connection has been made between both potential sides, the potential difference from one side instantly (speed of light) – Mac R. Jul 24 at 20:13

continued: runs across the wire no matter what the distance to meet the other side of potential difference at the load or switch to remain polar opposites of potential on either side of it to be able to " accelerate " the electrons ( in a DC circuit). – Mac R. Jul 24 at 20:19

Going back to AC, " They do not become positively charged under any circumstances " so then how is positive current possible in AC circuit. The sine wave starts e.g. 120V at +1 V then peaks at +120V then descends to 0V then descends further to -120V to return ascending again back to 0V. The positive voltage and current thereafter was only possible because of the positive charge present in that space of travel (in the wire), right or wrong. – Mac R. Jul 24 at 20:22

Positive/negative voltage is unconnected to positive/negative charge. The negative and positive voltages of an alternating current express that the electric field keeps changing its direction, not that it changes what type of charges are the basis for the field. – zwol Jul 24 at 23:58

@zwol that's very helpful. thank you. – Mac R. Jul 26 at 4:20

@zwol I was told that positive/negative potential tells/forces which way positive/negative current (charge) will go. – Mac R. Jul 26 at 15:03

I believe that's another way of saying the same thing. The direction of the electric field vector at any point will be the direction in which current flows. When we're talking about electric circuits, the field will (to first order) always point along the wire, so we can talk about "positive or negative" voltage instead of a full 3D vector field. – zwol Jul 26 at 15:12

@zwol "not that it changes what type of charges are the basis for the field. " - " positive/negative potential tells which way positive/negative current (charge) goes ". I am failing to see how both those statements are " saying the same thing. " – Mac R. Jul 26 at 22:00

The statements that are saying the same thing are "negative and positive voltages of an alternating current express that the electric field keeps changing its direction" and "positive/negative potential tells which way positive/negative current goes". However, notice that I deleted "(charge)". Positive/negative current is also only about direction, not about charge of the carriers. Read en.wikipedia.org/wiki/Electric_current#Conventions very carefully. – zwol Jul 27 at 14:25

@zwol " However, notice that I deleted "(charge)". "all right. Which brings us back to the post's question. "" Or is it that the electron carries only a positive charge in the first half of the cycle and then upon returning on the second half, it only carries a negative charge? "" if AC is positive current going one way in one half of the 50 hz cycle and negative current in the other half, and positive current is a flow of positive charge, then the electrons must carry that positive charge. Or so it seems in that " thought process ", is it wrong. – Mac R. 2 days ago

@zwol p.s. I already know about " convention ", this question was born from all that. – Mac R. 2 days ago

"AC is positive current [that is, current going one way] in one half of the 50 hz cycle, and negative current [that is, current going the other way] in the other half" - correct. "and positive current is a flow of positive charge" - wrong. Positive current is only about direction, like I said. – zwol 2 days ago

@zwol "" "and positive current is a flow of positive charge" - wrong "" I want to believe that soo bad. where can I find a factual academic text or article that states that same sentence. – **Mac R. yesterday******

I already pointed you at en.wikipedia.org/wiki/Electric_current#Conventions. Note in particular: "A flow of positive charges gives the same electric current, and has the same effect in a circuit, as an equal flow of negative charges in the opposite direction. Since current can be the flow of either positive or negative charges, or both, a convention is needed for the direction of current that is independent of the type of charge carriers. The direction of conventional current is arbitrarily defined as the same direction as positive charges flow." – zwol yesterday

(If you don't feel Wikipedia is sufficiently reliable, you should go to your local public library and ask at the reference desk for a high-school-level "electricity and magnetism" textbook.) – zwol yesterday

I am starting to think that in the " Electrodynamic Community " people are calling the flow of electrons through a wire: AMPs and the flow of charge Current. Is this correct or not. – Mac R. yesterday

@zwol " Since current can be the flow of either positive or negative charges, or both, a convention is needed for the direction of current that is independent of the type of charge carriers " but through a WIRE only electrons can flow, so I fail to see how in either DC or AC their can be positive current flow of positive charges if protons don't flow through WIRE. – Mac R. yesterday

(1) In a wire made of metal, only electrons can flow, yes. (2) Therefore, there can't be a flow of positive charges in a wire, but there can be a flow of positive current in a wire, implemented by electrons flowing in the opposite direction. (3) Amps and current are the same thing. More accurately, "amp" is the name of the unit of measure for current. – zwol yesterday

@zwol so we have established that at least in AC there is no positive charge present in either of the cycle halves and that in DC it might be the same. Also that, negative current and positive current through a WIRE is just the name given to either direction the ELECTRONS will flow/bump along due to push/force/accerlation from either of electric fields direction of travel running around/over the distance of the wire in an invisible field similar to a invisible magnetic field. if the previous is correct,

then where does charge ( negative, because in a wire ) come into play

. – Mac R. 17 hours ago
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