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RGB LED Fader – Easy

Building the circuit:

The parts list is as follows: A pack with all the parts is available here

Ω      One RGB LED (Common Anode)

Ω      One 1KΩ Resistor

Ω      Three 10K Logarithmic Potentiometers

Ω      Some Hook-Up Wire

Ω      A Breadboard

Ω      A 9V Battery

Ω      A 9V Battery Clip

The circuit:

RGB Fader circuit diagram


Above you can see the schematic for the circuit, the RGB LED is getting all its power from one pin through a 1K current limiting resistor.

The three potentiometers are acting as variable grounds for the LED. The whole thing is powered by a 9V battery.


Overview / how it works:

This circuit is an extremely simple design containing very few components! It simply uses 3 logarithmic potentiometers to control the colour and brightness of an RGB LED. An RGB LED contains three separate LED’s which can each be controlled individually. One is red, one is green, and one is blue. Using these three colours you can mix any colour you like, simply by combining them in different ways! This is what we use the 3 potentiometers to do. The RGB LED we use in our circuit is a common anode LED, this means that all three LEDs have one power pin and then each individual colour has one ground pin. We can vary the colour of each led by varying the difference in voltage between the power and ground pins, using our potentiometer. The potentiometer is hooked up between power and ground, so when the potentiometer is turned to ground, we get the full 9V potential difference (same as voltage) and more current will from. And when the potentiometer is turned to the full 9V there is no potential difference and no current will flow. We use logarithmic potentiometers because they are smoother for varying things like brightness of an LED or audio volume.

 

Images:

RGB LED Fader Circuit Breadboard image

 

First place in some hook-up wire with a black wire then 3 gaps, then a red wire then 2 gaps etc. three times. Then a red wire on it’s own.

RGB LED Fader Circuit Breadboard image

 

Then place some longer wires as shown from half way between black and red wires to the RGB LED area. (Far Right)

RGB LED Fader Circuit Breadboard image

 

 

 

 

 

 

 

 

 

 

 

 

 

Then place your current limiting resistor between the red wire, and the second most right pin from the orange wires.

RGB LED Fader Circuit Breadboard image

 

 

 

 

 

 

 

 

 

 

 

 

 

Then place your RGB LED in with the four pins going to the 3 orange wires and the power. The longest leg should go to the resistor.

 RGB LED Fader Circuit Breadboard image

 

 Finally put on the three potentiometers, with one pin going to a black, the middle pin going to an orange, and the final pin going to a red wire for all three. Power it on and twist!

RGB LED Fader Circuit Breadboard image

 We got some pretty cool colours when we tried! Experiment and see what you can make!

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