# How do electrons flow in a basic electronic circuit?

1. Nov 18, 2009

### glenn101

Hey guys, I'm going to university next year to complete a degree in electronics engineering and I'm hoping to get a head start.

Ok I've attempted to read several online materials to try and create a mental model of what occurs in an electronic circuit. Lets assume its a basic circuit with a battery, copper wires, and a load. And I'll also assume non-conventional current i.e. electron flow from negative to positive terminal inside battery. Ok so beginning from the battery, my first question arises, I've read that inside the battery there is an electric field directed from the negative to the positive terminal, is there a build up of electrons at the positive terminal of the battery to induce this field?

From there work is done on the electrons from the chemical reactions inside the battery to push electrons against this electric field gaining electric potential in the process, so once the electrons leave the positive terminal of the battery, is there another electric field created in the circuit to push the electrons around the circuit whilst reducing electric potential eventually returning to the negative terminal?

I'm assuming there is, if so, what is creating this electric field?

2. Nov 21, 2009

### vk6kro

I've read that inside the battery there is an electric field directed from the negative to the positive terminal, is there a build up of electrons at the positive terminal of the battery to induce this field?

The electrons that flow out of a battery do not "bunch up" on the negative terminal.
Before you completed the external circuit, those electrons were spinning around Zinc atoms on the Zinc electrode of the battery.
The Zinc dissolves in the electrolyte to become Zn++, releasing two electrons.
At the positive terminal, there are a lot of Hydrogen ions that are able to use returning electrons to become Hydrogen gas.

The electrons do not actually move through the battery.

These reactions depend on the kind of battery it is, but the principle is the same.

The net result of these chemical reactions waiting to happen is that there is a potential difference across the battery. You can measure it with a meter. This voltage is due to the Oxidation and Reduction potentials of the reactions happening at the terminals.

After that, Ohm's Law applies and the current that flows depends on the external resistance and the internal resistance of the battery.