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# Electricity.......... Watch

1. Ive got a pretty incomptent physics teacher for gcse so im reading up over topics in the holidays.

If anyone could answer these questions, it'd be great
What's the difference between current and charge?
Which way does the charge flow?
Which way does the current flow?
What's the difference between parallel and series circuits?
2. Charge is just charge, e.g. electrons have a charge of -e. Current is the flow of charge (it is measured in coulombs of charge passing through a point in the circuit per second). Conventional current flows from positive to negative, the opposite direction to electron flow which is from negative to positive. In a circuit, the electrons are the charges and so that is the direction in which the charge moves. You can have electrolysis though in which ions are the charges which move, in which case there are both positive and negative charges, again the negative charged ions moving from negative to positive like electrons whilst the positive ions move in the opposite direction. A series circuit is on in which components are joined one after another, whereas a parallel circuit is one in which components are joined over one another. A circuit can have both parallel and series parts to it.
3. (Original post by alphanick)
charge is a property representing the flow of electrons, current is one unit of charge (si unit = coulombs) per unit of time (second), so it is q s-1, or amperes, a. This is because charge and current are unified by:

$q=it$

$\therefore i=\frac{q}{t}=qs^{-1}$

charge is the flow of electrons, so it flows from the negative terminal to the positive terminal.

Conventional current flows from the positive terminal to the negative terminal.

In series circuits, components are connected to each other by a wire. In parallel circuits, components are connected by wires which connect to the existing wire (which is in series) as so - left = parallel, right = series:

thank you!!!!!!!
4. Btw, Can anyone tell me the circuit rules for each type of circuit, parallel and series?
5. [QUOTE=AlphaNick;48694240]In series:
- current is equal everywhere

$I=I_{1}=I_{2}=I_{3}$

- total voltage / p.d. is the sum of all other p.d.s of components

$V=V_{1}+V_{2}+V_{3}$

- total resistance is the sum of all other resistances of components

$R=R_{1}+R_{2}+R_{3}$

In parallel:
- current is the total sum of all components

$I=I_{1}+I_{2}+I_{3}$

- voltage / p.d. is equal for all components

$V=V_{1}=V_{2}=V_{3}$

- resistance is the reciprocal sum of all other resistances

$\frac{1}{R}=\frac{1}{R_{1}}+\frac{1}{R_{2}}+\frac{1}{R_{3}}$

(you don't need to know this one for GCSE)
[/QUOTE

Well, Mr, you've just saved my life
My physics teacher is absolutely crap plus i've not done anything properly on circuits in KS3 either so literally this could be the jump from one grade to another.

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Updated: July 23, 2014
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