This is the circuit of LED color fade effect. Just like the name of the circuit, the light intensity of LEDs in this circuit will fade from high  intensity to low intensity and then off.

Here the final result preview:

30 uF condensator and the resistor marked with blue 100k control the speed of the fading. You can replace the 100 kilo ohm resistor with 100k linear potentiometer so you can adjust the speed any time. The supply voltage is 5VDC, you may use battery or power supply adapter to operate this LED color fade effect circuit.

You can make the circuit even simplier by leaving out other of the transistors and those leds that are connected to it. Good for power led pulsing etc.

LM324 is an OP-Amp amplifier. There 4 op amp, and we just use 2 op amp in above circuit diagram. You may use the other 2 op-amp to build another similar circuit. Transistor is BC547 and the led is ultra bright red with 220 ohm resistor in series.

## 5 thoughts on “LED Color Fade Effect”

1. circuit diagram Post author

please check the diagram, you’ll fine gnd (-) there.

2. Shamol kumar(joy)

Please tell me,how can I input negative volt in this circuit.This circuit diagram picture only shows positive voltage input system.

3. LED hog

GREAT! just edit a little more carefully…by the way: there is no such thing as a condensator. Its just a condenser, or a capacitor…:) GREAT WORK!

4. Kaleemullah

Hi dear its me kaleemullah nizamani and i want to help u dear you have said that three step
but there is not a three step.. in ur last sentance u have said that 3 step one by one so first of
all you have to devide 1000 by 3 u wil got 333.33 like some thing that so actully ur step will be
about 333… and i gona share with u some about that how to calculate a resistor for led using
any kind of voltage….. you have to apply this formula
R = (Vs-Vl)/I
R mean Resistor which u wana Need
Vs mean voltage of supply
Vl mean Led required voltage
I mean Led required current
I hope Now u can run led on any voltage
By using This Formula.

5. Mustafa

If i have More then 1000 LED and I want to display in three Step so How will i connect and what will be the register value and the voltage used. but that should be in 3 step one by one.
Thanking you

with regard
Mustafa