Series Circuits

Learning the difference between Series and Parallel circuits is important. 

In series circuits, the components are added in 'series' or in one line, as if they were all on one wire. The thing about this type of circuit is that if the wires break, the whole circuit stops working.
This also means that the potential difference is shared throughout the circuit.

You might get an equation like this :
Vtotal = V1 + V2 + V3.

If we were to put a 12-volt cell or battery, and have two filament lamps on the circuit, both lamps have to add up to 12 volts

On the other hand, current is the same everywhere in the circuit. To measure it, we use ammeters, which are placed in series, and since they measure current, we can place them anywhere in the circuit.

Resistance is how much the component resists electricity, and the total resistance is a sum of how much all components resist, so to calculate the resistance in ohms, we need to know how much power our components resist. 

So, let's take a circuit and connect two filament lamps, one lamp requires 4 ohms, and the other requires 2 ohms.
The total amount of ohms is about 6 ohms, since it is 2 + 4.

Let's use the same 6 ohm circuit above and calculate the resistance of a single component.
We can use the equation "V=IR", which is named Ohm's law, the 'V' in the equation means voltage.
So, first we find the battery, which is 12v or 12 volts. 
We then divide the 12 volts by 6 because that's how many ohms are flowing into the circuit, to get 2A or two Ammeters, then which then means that the component had 2A of resistance, then we multiply the 2A by 2 ohms or 2*2 to get 4 volts. 

Something to keep in mind is that Ammeters do have resistances, it is such tiny resistances that we can practically ignore them, now if we want to get the voltage of the second component, we would need to do the equation again, or we could just do 12-4 to get us 8.

Because we know how many volts are flowing through the circuit, which is 12, we can just skip doing the math, so doing 12-4 gives us 8, so that means that the second component needs 8 volts.

There is another way to find out how much voltage each component uses in the circuit by using a Voltmeter, which is connected in parallel to the component which we want to check, so if we connect it to the 8 volt component, it would display 8v.

Keep in mind that even though the voltmeter is connected in parallel,
we still consider the circuit to be in series, also the components that have a higher resistance will require more voltage, than components that resist less.