How to Build a 10 Segment LED Bar Graph Circuit


A 10 segment LED bar graph is a visual display consisting of 10 individual LED segments arranged in a linear format. Each LED segment represents a specific level or quantity, and the entire bar graph collectively indicates the overall level. Building a 10 segment LED bar graph circuit allows you to create a visual representation of varying quantities or measurements.Basically, it can simulate bar graph results. For example, if we’re measuring battery power in a circuit, the LED bar graph can project the strength. If all 10 LEDs are lit, this could mean full strength. If 5 LEDs are lit, this could mean it’s at half strength. If 1 or no LEDs are lit, it can mean the battery is dead. So uses such as this are many times what LED bar graphs are used for.

How to Build a 10 Segment LED Bar Graph Circuit with Manual Pushbutton Control

Required Components

  • 10 LEDs (Light-Emitting Diodes)
  • 10 220Ω Resistor
  • 10 Pushbuttons
  • 10 3v Battery

Circuit Diagram of the LED Bar Graph

How to Build a 10 Segment LED Bar Graph Circuit

Working Principles of the LED Bar Graph Circuit

The working of the LED bar graph circuit involves controlling the individual LEDs based on the input level or data being represented. The circuit uses transistors as switches to turn on or off each LED segment according to the desired level. The input signal or data determines which LEDs light up, providing a visual representation of the input level.Then connect each of the anodes of the LED bar graph to positive voltage via a pushbutton. We use 220Ω resistors for each of the LEDs to limit current to the LEDs, so that an LED doesn’t blow out.

The resistors function to limit current but also as pull-down resistors. Pull-down resistors are resistors that are normally in a LOW state (grounded) but when the pushbutton is pressed becomes a HIGH state (connectedt to positive voltage).

When the pushbuttons are unpressed, the LEDs are off. They are connected to ground, without any connection to the positive voltage.

When the pushbuttons are pressed down, the LEDs turn on. They are now connected to the positive voltage source and the circuit is now complete. Current flows from the positive voltage source down to ground to light on the LED.

Building the LED Bar Graph Circuit

Now, let’s walk through the step-by-step process of building the 10 segment LED bar graph circuit.

Step 1: Gathering the Components

Collect all the required components mentioned earlier. Ensure their quality and compatibility with each other.

Step 2: Circuit Diagram

Create a circuit diagram to visualize the connections and components’ placement. This diagram will serve as a guide for assembling the circuit.

Step 3: Assembly and Connection

Follow the circuit diagram and assemble the LED bar graph circuit on a breadboard or a PCB (Printed Circuit Board). Connect the components as per the diagram using appropriate wires or soldering.

Applications of LED Bar Graph Circuits

LED bar graph circuits have various applications, including:

  • Audio equipment: Volume level indicators, equalizers
  • Measurement instruments: Signal strength indicators, battery level indicators
  • Industrial monitoring: Process control, level monitoring
  • Home automation: Environmental monitoring, energy usage displays

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