Electronics Course Part 1 - Fundamentals

Electronics - The Fundamentals

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Its easy to be overwhelmed by the huge variety of circuits and components. We aim to put you on the right path to this exciting and rewarding hobby.

To make anything with electronics, you need to create a circuit. A circuit is a pathway for the "electricity" to travel around. Like Mo Farah on a track, it runs round the circuit from start to finish. Instead of runners, we have "ELECTRONS". These tiny particles are inside our components, wires and pretty much everything else.

When we get a working circuit, they travel around, and this is what causes our circuit to do something.

In our circuit, the start and finish is the power source

We can get power from different sources, depending on what the finished circuit will do, the easiest and simplest is a battery.

Other possible power sources

• AC Mains
• Dynamo, or generator
• Solar Energy
• Radio Waves

The power source has lots of electrons, all ready to get into your circuit and cause something to happen, your wires and components are also full of electrons. So why do we need a power source?

We need the electrons to move! so we push them along by adding at one end and pulling them at the other. Some things are easy to push the electrons through, like copper wire, others are harder because they resist the flow. Here is a look at the flow in a wire.

We need some knowledge here. Why does a power source move the electrons? It uses EMF 

EMF stands for Electro- Motive- Force. We can measure the stength of this "push" or "pressure".

When you measure the pressure in Tyres, you measure the PSI, In electronics we measure the VOLTS.  A higher voltage is the same as saying we have a higher EMF.

We can also measure how many electrons we are moving. When you open a tap, you could measure the flow as Litres/Minute. In electronics we measure AMPS.

• Driving Force = VOLTS - abbreviation (V) - symbol (v)
• Flow = AMPS- abbreviation (I)- symbol (A)

 Can you see that for a given force, there will be a certain flow?
Imagine you are standing in a queue, everyone squashed up together, you are at the back :(
Now push the person in front of you.

Did the person at the front  of the queue move? Good, that was easy. Do it again, but push a lot harder,
Did the queue move quicker? Good.

Now imagine that the people in the queue are ready for you! How much harder do you have to push to make the person at the front move?

The queue was resisting your force, so you needed a bigger force to get the same result. In electronics that resistance can be measured, we use OHMS 

• Resistance = OHMS- abbreviation (R)- symbol (Ω)

The three measurements are related to each other, and they are really important.
So important, that they have there own law governing the relationship between them

OHMS LAW

For a given Force in VOLTS, through a given resistance in OHMS, there will be a specific flow in AMPS

The easy version

Volts = Current x Resistance
V=IxR
If you know any two, you can calculate the other

Example, you measure the voltage as 10v, and the resistance as 10Ω

The current flowing  10(V)= Current x 10(R)

You could think "What times 10 equals 10?" and come up with the answer 1, (1 Amp)

Or if you remember maths from school, you can transpose the formula to be

I=V/R

Current = 10(V) / 10(R) so Current = 1 (Amp)

Don't get too concerned about the maths side of it, as we go through the course, most will be worked out for you, but its good to know where the results come from.

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