Let there be light!

Hello, everyone!

In this post, we will discuss about the simplest of all circuits, a light source connected to a power source.

Back in the days, we use ordinary incandescent bulb connected to a power source to illustrate the most basic circuit in electronics. But, times change and we now use an LED which is more power efficient.

The main difference between an incandescent circuit and an LED circuit is the introduction of a component called a resistor. For now, don’t worry about the resistor, I will post a separate article about that.

For this basic circuit, we need the following components:

  • LED
  • 220Ω Resistor
  • 5V DC Power Source
  • Lead wires
  • Breadboard

Consider the diagram below:

On the left side of the diagram, you will see the symbol for a DC power source with a rating of 5V. At the top of the diagram is a 220Ω. On the right s the LED symbol.

The following image shows the actual circuit prototype:

The red wire is connected to the positive terminal of the DC source, while the black wire is connected to the negative terminal. The LED must be connected to a resistor to limit the amount of current passing through it. Otherwise, the excessive current will damage the LED.

So, what is happening here? The battery supplies the power to the circuit. The resistor restricts the amount of current passing through the LED. When power is applied, the LED lights up. Cool, huh? 🙂

In the next article, I will discuss the technical aspect of this simple circuit. For now, enjoy that first light illuminating the path to your electronics discovery.


Why do LEDs need resistors?

Electronics All-in-One For Dummies, by Doug Lowe

A free, user-friendly program for making electronic circuit diagrams.


  • Use protective gears, such as goggles, when working with electronics.
  • Small electronic components are choking hazards. Adult supervision is required for minors.

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