Basic Electrical Theory

[His Dudeness]

 I think understanding electrics is the hardest part of diy mechanics so a thread on basic electrical theory might be useful for people To get a good understanding of the basic theory I’d recommend reading chapter one of this site https://www.allaboutcircuits.com/textbook/direct-current/

Here’s my quick explanation of Voltage, Current and Resistance. To understand electrics you have to look at the atom. Atoms have positively charged protons at their centre in the nucleus and negatively charged electrons orbiting around the outside of the nucleus. This is shown below in an atom of Copper







The Protons are held in the nucleus with a lot of force. The electrons orbit around the outside of the nucleus and are held with far less force. This means that electrons can move from one atom to another atom. Since the electron has a negative charge the atom that loses the electron becomes relatively more positively charged and the atom that gains the electron becomes more negatively charged.





In nature atoms want to be in a Neutral state meaning that they want to have an equal number of positive protons and negative electrons. Because of this when one atom is positively charged from losing an electron and the other atom is negatively charged from gaining an electron a force is created between the two atoms that attracts the atoms together. This “pushing” force is called Voltage. So Voltage is a force that is caused by a difference in electrical charge between two points and it’s caused by one point being more negatively charged and the other point being more positively charged. A battery creates this difference in charge through a chemical reaction. The negative side of the battery has an excess of negative electrons and the positive side of the battery has a lack of electrons so a Voltage “pushing force” is created between the two points.

When a conductor is applied between the positive and negative points of the battery a Current flows. Current is the continuous, uniform flow of electrons through a conductor caused by a Voltage “pushing” electrons from the negative side to the positive side.
A conductor is a material that allows electricity through it easily. Conductors allow electricity to flow easily because they have a single electron in the most outer orbit of their atom that they lose easily, called a free electron. Here is a short video on copper that explains how conductors work

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Resistance is opposition to the flow of current. Resistance is caused by collisions between the electrons and the atoms. Higher resistance means more collisions. Collisions cause the atoms to gain energy and vibrate this energy is given off in the form of heat energy. In some materials no electrons are free to move so no current flows these are insulators.


This is an excellent video that explains everything that I typed. Definitely watch it

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I'm a newb to electrics but I think what I wrote is correct and might be useful to other newbs. I'll do another post on basic circuits and Voltage drop. Then on reading wiring diagrams and how the electrical components on a bike work. Once you get your head around the basics the rest becomes clear.

[Millietant]

Holy crap !!


I just imagined millions of these tiny little electricity gremlins running from the plus terminal on my battery, through my wiring, round to the negative one. If there's a break, or a missing connection in the wires, then the gremlins can't make it.


The wiring diagram is the road atlas the gremlins use to find their way around my bike, to each of the electrical components.


I don't know where the gremlins come from, or what they eat, but I'm happy they're there 


Seriously though, it'll be nice to get to the science behind all of this - so thanks for the info 

[His Dudeness]

Holy crap !!


I just imagined millions of these tiny little electricity gremlins running from the plus terminal on my battery, through my wiring, round to the negative one. If there's a break, or a missing connection in the wires, then the gremlins can't make it.


The wiring diagram is the road atlas the gremlins use to find their way around my bike, to each of the electrical components.


I don't know where the gremlins come from, or what they eat, but I'm happy they're there 


Seriously though, it'll be nice to get to the science behind all of this - so thanks for the info 

No problem Not meaning to confuse the issue but the gremlins actually go from the negative to positive. What??  If you watch those videos or read the website they all explain it as going from negative to positive because that's what happens. Remember electricity is all about the flow of electrons and electrons have a negative charge. It's the electrons that are moving through the circuit so its negative charge that is moving from the negative terminal of the battery, where there's a surplus of electrons, to the positive terminal where there's a lack of electrons. That's what is really happening in a circuit and it's called Electron Flow Current. Negative to positive.

However when electricity was first being developed they didn't know about atoms or electrons and they guessed that current was positive charges flowing through the circuit, from the positive terminal to the negative terminal. That is called Conventional Current flow. They went so long thinking Conventional Current Flow was right that when they discovered it wasn't they decided it was too much trouble to change all the schematics and wiring diagrams so they left them as Conventional Current Flow. From positive to negative and really it doesn't matter what way you represent the flow of current as long as you're consistent in the direction you do it. It does make it confusing when you start learning about it though! All the books explain it as going from negative to positive and all the schematics show going from positive to negative

If you're trying to read a wiring diagram or fix a bike you use Conventional Current Flow because that's how the wiring diagrams are drawn but if you're try to get your head around the theory it'll mostly be in Electron Flow current.
There's the explanation of Conventional Current Flow and Electron Current Flow https://www.allaboutcircuits.com/textbook/direct-current/chpt-1/conventional-versus-electron-flow/

[limax2]

I found this very interesting and easier to understand than the wife. Strangely she preferred to watch Emmerdale or some such fiction.  [size=78%] [/size]

[limax2]

I don't know where the gremlins come from, or what they eat, but I'm happy they're there   

I don't know what they eat either but the white stuff they leave on battery terminals is called ampshit.

[His Dudeness]

I found this very interesting and easier to understand than the wife. Strangely she preferred to watch Emmerdale or some such fiction. 

Good I'm glad you found it interesting I'll keep adding to it if it's useful. That first post hopefully gets across a good idea of what Voltage, Current and Resistance are. For working on bikes the exact scientific definitions aren't that important but if you can get a clear picture in your head of what Voltage, Current and Resistance are the rest of electrics like wiring diagrams or figuring out how components work comes to you a lot easier.

To summarise that first post it basically says atoms have positive protons and negative electrons. Atoms always want to have an equal number of positive protons and negative electrons, which is to say that they always want to be electrically balanced. When they're not balanced (due to gaining or losing electrons) the need to get back to being balanced creates a force between areas of relatively opposite charge that attracts the opposite charge together so the atom is balanced again. That force is called Voltage.

In a battery the imbalance is caused by an excess of electrons at one point and a deficit of electrons at the other point causing one point to be more negative and the other to be relatively more positive. When you provide a path for the electrons to flow (i.e. a conductor) the Voltage caused by the imbalance "pushes" electrons through the conductor. The battery keeps "pushing" electrons until both sides of the battery are balanced and have equal charge (i.e. the battery has 0 Volts difference between the positive and negative sides). The uniform flow of electrons along the conductor is called Current. Resistance is the opposition to the flow of Current. 

[deeteefifty]

Good stuff simply put. Going back to basics is worthwhile now and then. Back in the 1980s my college lecturer used to to kid us with a half truth that the power supply companies were conning all of us in a big way because all of the power they produce returns to them in the complete circuit.

[celticdog]

Guys! Be careful, I've heard if you accidentally split one of them atom thingys you're in a bit of a sticky situation.

[His Dudeness]

Here's a few more good videos on atoms and electricity

[His Dudeness]

Good stuff simply put. Going back to basics is worthwhile now and then. Back in the 1980s my college lecturer used to to kid us with a half truth that the power supply companies were conning all of us in a big way because all of the power they produce returns to them in the complete circuit.

Guys! Be careful, I've heard if you accidentally split one of them atom thingys you're in a bit of a sticky situation.

Yeah my Lead underpants are on just in case

[His Dudeness]

Here's a bit more on this stuff. Hopefully the attachment works. I wrote about series and parallel circuits because I think if you understand the first post above on voltage, current and resistance and you understand what's happening in series and parallel circuits you'll have the fundamentals of electrics. Doing the calculations on series and parallel circuits isn't that important for working on bikes but I think doing the calculations is the best way to get your head around what's happening in the circuit