LEDs Oscillator

This article shows you how to make an oscillator from a blinking LED or color-changing (color cycling) LED.

Figure 1: LEDs Oscillator.

In case you do not know, color-changing LEDs change in color every second, and blinking LEDs turn ON and OFF every second.

You can see the circuit working in this video:

You do not need two LEDs. You can create an LED oscillator with just one blinking LED. However, this article will show you how adding a second LED (even a non-blinking one) will make the output signal more interesting.

Circuit 1

I simply connected a color-changing LED in series with

a resistor to 3 V power supply:

Figure 2: Design the Circuit 1.

I used a small breadboard to make the circuit:

Figure 3: Make the Circuit 1.

I connected the non-grounded LED pin to Hantek 6022BE USB Oscilloscope:

Figure 4: Testing Circuit 1.

The amplitude was only 62.7 mV peak to peak. You might think we need a blinking LED that turns ON and OFF. However, read what happens in the next section of this article.

Circuit 2

I modified the circuit by simply adding a regular (not blinking LED) in series with LED and resistor.

Figure 5: Design the Circuit 2.

I connected the circuit 4.5 V battery holder that is almost 5 V:

Figure 6: Make the Circuit 2.

I connected the non-grounded LED pin to Hantek 6022BE USB Oscilloscope:

Figure 7: Testing Circuit 2.

Now the amplitude is 267 mV and you can clearly see it in the changing frequency square wave oscillation in the plot.

Figure 8: Testing the Circuit 2 Photo.

Conclusion

The oscillating component does not have to be a blinking LED. It could be a buzzer, electric bell, or motor.