lastly, solder the third resistor between pin 7 & pin 2 of the IC.Ĥ) After that solder a 100K pot between pin 1 of the IC and the 39K resistor. the second resistor between pin 4, pin 3 & pin 6 of the IC. the first resistor between pin 8, pin 6 & pin 3 of the IC. You will need the following parts to build this project: S.NoĢ) After that, solder a 100K resistor between pin 7 & pin 5 of the IC.ģ) After that, solder the three 4.7K resistors. Hence, an astable multivibrator is also a pulse generator or a square wave generator. If these time constants are equal (R and C are equal) then a square wave will generate with a frequency of 1/1.4 RxC. With no external signal applied, the transistors alternately switch from cutoff to saturation state at a frequency that RC time constants of the coupling circuit determine. An astable multivibrator is a free-running oscillator that switches continuously between its two unstable states.

Here, we are using the LM358 in Astable multivibrator mode. It can be considered as one half of the LM324 Quad op-amp which contains four op-amps with a common power supply. The heart of this circuit is an LM358 IC. So, in today’s tutorial, we are going to go over a step by step process on How To Make a Breathing LED Circuit Using LM358 Op-Amp IC.

The RC circuit allows the user to control the fade duration of the LEDs. Generally, almost all breathing LEDs follow the same configuration scheme, an astable multivibrator generates a free-running square, whose frequency is being regulated by a simple RC circuit connected in parallel to the multivibrator. These fancy breathing LEDs are mostly used for decorative purposes in applications such as advertisement banners, Christmas lights, street signs, etc. Related posts: What is a Breathing LED Circuit?Ī Breathing LED circuit is a simple electronic circuit that fades in and fades out periodically.

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