Monday, 18 January 2016

How To Make A Simple LED Dimmer Circuit

Do you ever wanted to add a brightness control feature to any of your LED projects? Here is a simple circuit involving just a 555 IC with no use of any micro-controllers. The circuit can be soldered to a perforated board or can even be built on a breadboard.

Note: This project is a part of the Ten Breadboard Projects For Beginners series published by me on instructables.

Description: This is a project used to change the brightness of an led by varying the resistance using a potentiometer which has a knob that can be turned to set it at a particular value. The circuit is somewhat similar to PWM (pulse width modulation) circuit which is used to control the speed of motors. The brightness is altered by switching the led between on and off at a fast rate which reduces the brightness. The rate is controlled by the potentiometer thus changing the brightness.

Difficulty: Medium

Parts List:
  • 1x 555 timer ic
  • 1x 1K resistor
  • 1x 220 ohm resistor
  • 1x 100n capacitor
  • 2x 1n4001 or 1n4148 diodes
  • 1x 50K or 47K potentiometer
  • 1x LED

Circuit Diagram (Made using Fritzing):

Breadboard Layout (easier to follow, Made using Fritzing):

Instructions: Connect everything according to the layout given above. Make sure you connect the diodes in the right way as they have polarity. Switch the circuit on and turn the pot slowly. You will observe that the brightness of the led changes.

Related Project: Check out my Desktop Lamp instructable that uses a similar circuit to change the brightness of 36 leds in a reading lamp.

Circuit Source:

This is the end of this article. If you have any questions, feel free to comment below.
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1 comment:

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