Basic Electrical Quantities and Breadboard Explained

In the last post (here), we were introduced to the basic electrical quantities; Voltage (V), Current (I) and Resistance (R) and we used the analogy of rocks sliding down a cliff to explain how they are related. Now, there is an important mathematical equation that binds all 3 quantities.

This is known as Ohm’s law. Ohm’s law states that the current through a conductor between two points is directly proportional to the potential difference or voltage across the two points, and inversely proportional to the resistance between them.

What this means is;

V = I*R

I = V/R

R = V/I

We would be using this equation when designing our circuits to know the appropriate values of component such as resistors to use to ensure we do not burn components such as LED’s due to excessive current.

Some Quick facts about circuits

There needs to be a complete path from the energy source (power) to the point of least energy (ground) to make a circuit.If there’s no path for the energy to travel, the circuit won’t work. 

All the electrical energy gets used up in a circuit by the components in it. Each component converts some of the energy into another  form of energy. In any circuit, all of the voltage is converted to another form of energy (light, heat, sound, etc.).

The flow of current at a specific point in a circuit will always be the same coming in and going out. Electrical current will seek the path of least resistance to ground. Given two possible paths, more of the electrical current will go down the path with less resistance. If you have a connection that connects power and ground together with no resistance, you will cause a short circuit, and the current will try to follow that path. In a short circuit, the power source and wires convert the electrical energy into light and heat, usually as sparks or an explosion. If you’ve ever shorted a battery and seen sparks, you know how dangerous a short circuit can be.

 (Source: Arduino Projects Book)

Another important concept we need to understand is the arrangement of components on a circuit board. This is best explained practically using a breadboard and no the breadboard isn’t made of the bread we eat, how awkward would that be! The breadboard is where we will build most of our circuits while prototyping because it is a solderless board and is very easy to work with. There are two arrangement patterns on a circuit board; it’s either a Series connection or a Parallel connection. But first, let us explain how the breadboard works.

This video gives a detailed explanation of how breadboard’s work and connecting components such as resistors and LEDs on a breadboard. It also gives an introduction to jumper wires.

 (Credit: Science Buddies)

Now that we know hoe breadboards work, I endeavor you to build your own first circuit and make that LED light up. We will look at connections in series and parallel in our next post. Ciao!