Lighting Systems
In this section, we are going to introduce you to the basic concepts of lighting systems and circuit components.
Basic Electric Concepts in Lighting Systems
Current: It is the flow of electric charge over time. The amount of electricity that flows through a circuit is determined by the current. Furthermore, the current affects the efficiency and brightness of the light source. Hence, for example, when designing and building an electric circuit to light an LED, one must make sure that the current flowing through the LED is within certain limits. This is to avoid having too much current flowing through the LED and thus avoid any problems or damage.
Voltage: This is what determines the brightness of an LED or bulb in an electric circuit. In other words, if you want a very bright light you should supply a higher voltage but if you want a dim light you should supply a low voltage. Therefore, when designing your electric circuit, you should make sure that the voltage that is being supplied is consistent with the desired brightness.
Resistance: From the name, it opposes the flow of electric current in a circuit. In the case of lighting systems, its main purpose is to control the amount of current flowing through, for example, an LED. This is mainly to avoid any current overload, so no component gets damaged.
Ohm’s Law
How do we determine the values such as resistance? This is explained through Ohm’s Law.
Ohm’s Law is expressed as follows:
This law states that the current flowing through a component is directly proportional to the voltage across it and inversely proportional to its resistance. As we can see, Ohm’s law gives us an understanding of how current, voltage, and resistance are related and provides designers with the means necessary to accurately set values for components such as resistors to achieve the desired lighting in our circuit.
Basic Electric Components used in Lighting Systems
Resistors: They are electrical components that obstruct the flow of an electric current. They control the amount of current flowing through a circuit. For example, in an LED circuit, resistors are vital as they limit the amount of current passing through to avoid damage to the LED. Resistors also play a role in controlling the brightness of the light emitted by the LED.
Diodes: They are semiconductor devices that allow a current to flow only in one direction and block the flow of the current in the opposite direction. An example is a Light Emitting Diode (LED) which is a type of diode that emits light when a current flows through it in the forward direction. As seen in the image, an LED has two pins where one is the anode (+ve), the longer pin, and the other is the cathode (-ve), the shorter pin. In some LEDs, the pins are of the same height, in that case, the flat side of the LED indicates the anode.
The current will flow into the anode; therefore, the anode should be connected to the positive side of the power source. The current will flow out of the cathode; therefore, the cathode should be connected to the negative side of the power source.
Before starting with the first task of building your own electric circuit to light an LED, let us introduce the Breadboard.
The Breadboard
You can think of a breadboard as your canvas and your electrical components as your paint and tools to create your electrical circuit. The breadboard allows us to connect many components together in order to build electric circuits. Along the sides of the breadboard are columns which are known as ‘Power Rails’ that are marked with +ve and -ve labels. These columns are responsible for providing power to the components that make up our electric circuit by connecting to a power source such as a battery.
It is important to understand how the rows and columns on a breadboard are connected. In the following image, we can see how the entire row is highlighted in green; this means that they are all connected to one another. Hence, when you add a component to the breadboard, each pin of the component should be connected to a different row to ensure proper electrical connectivity and avoid short circuits.
CHALLENGE!
Now you’re going to build your own electric circuit to light a Light Emitting Diode (LED) using the breadboard and electrical components provided in the kit!
The below video is a step by step guide on how to build your circuit.
Download the video transcript
RGB LED
In your next challenge you are going to be asked to build a circuit to light an RGB LED. What is an RGB LED?
RGB is an acronym for red, blue, and green; therefore, an RGB LED is an LED that can basically create any color of the rainbow. In other words, an RGB LED is simply three LEDs that share either a cathode or an anode. In RGB LEDs, the LEDs are very close to each other; thus, we can obtain any color we want by controlling the intensity of these 3 LEDs. It has four pins which are red, blue, green, and a common cathode (the negatively charged electrode by which electrons enter an electrical device). In our example, we have a common cathode, so the cathode pins of the internal LEDs are all connected to a single pin.
CHALLENGE!
Build a circuit to light up an RGB LED using the breadboard and the electrical components in the kit!
The below video is a step by step guide on how to build your circuit.
DONE!
Congratulations on plunging into the world of electricity! Understanding its principles electrifies your potential in myriad applications, from lighting up homes to powering cutting-edge innovations. Keep sparking curiosity and exploration, as your grasp of electricity will ignite pathways to new discoveries and advancements in energy technology.