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Creating a Blinking LED Circuit

Aug 22, 2024

Blinking LED Circuit Tutorial using 555 Timer IC

Introduction

  • Overview of creating a blinking LED circuit using 555 Timer IC in astable mode.
  • Ability to toggle LED on/off at regular intervals.
  • Modifying flashing rate by changing timing resistor or capacitor values.
  • Optional: Connecting an additional LED for alternating flashing.
  • Use of a potentiometer for dynamic adjustment of flashing speed.
  • Relay module may be needed for heavy loads (e.g., AC lights or LED strips).

Components Required

  • 555 Timer IC
  • Resistors:
    • 1k ohm resistor
    • 100k ohm resistor
  • Capacitor: 10uF
  • LEDs
  • Resistor for LED: 220 ohm (check values for different supply voltages)
  • Potentiometer (optional for speed adjustment)
  • Relay Module (optional for heavy loads)

Circuit Setup

  1. Power Rails:

    • Positive rail
    • Negative rail

  2. 555 Timer IC Placement:

    • Notch facing up.
    • Pin numbering starts from pin 1 to pin 8.

  3. Connections:

    • Pin 1 to negative rail.
    • Pin 8 to positive rail.
    • Connect pins 2 and 6 together.
    • Connect pins 4 and 8 together.
    • 1k ohm resistor between pin 7 and pin 8.
    • 100k ohm resistor between pin 6 and pin 7.
    • Connect 10uF capacitor (negative to pin 1, positive to pin 2).
    • Extend output from pin 3 to LED (anode to the output, cathode to negative via 220 ohm resistor).

  4. Additional LED for Alternating Flash:

    • Cathode of another LED to output pin of the 555 IC.
    • Anode to positive rail via series resistor.

Understanding Circuit Functionality

  • Operation of 555 Timer:

    • Pin 2 turns ON output when voltage < 1/3 of supply voltage.
    • Pin 6 turns OFF output when voltage > 2/3 of supply voltage.
    • When power is on, capacitor starts in discharged state, allowing output to turn ON.
    • Capacitor charges via resistors; when voltage exceeds 2/3 of supply, output turns OFF.
    • Cycle repeats continuously.

  • Capacitor & Resistor Influence:

    • R1 affects both charging and discharging of capacitor.
    • Increasing R1 value reduces flashing rate (longer charge/discharge time).
    • Increasing capacitor value also reduces flashing rate.

Calculation Formula

  • Use provided formula to calculate resistor and capacitor values for desired time period or flashing rate.

Conclusion

  • Summary of the setup process and functionality.
  • Invite to subscribe for more tutorials.

Full transcript