What is the use of these two capacitors here. The circuit is working just fine without them also.
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1 Answer
A circuit usually works well without the capacitors but they make the circuit much less sensitive to electromagnetic noise.
The purpose of the capacitors is to stabilize the power supply. An integrated circuit may draw lots of power for a very short time, and this may introduce a high amount of noise on the power rail on the PCB. The capacitors serve as a local power storage so the chip doesn't draw power from the power rail.
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2Note that it is important that the capacitors are physically close to the circuit, otherwise their effect doesn't apply.– PMFCommented Nov 6, 2020 at 18:49
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Thanx for answering. One more thing ...what do you mean by physically closer? Any specific distance? Commented Nov 6, 2020 at 19:48
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"Physically close" means as close as possible. Ideally they should be mounted right onto the circuit pins. In practice, this means right next to the chip.– Ole WolfCommented Nov 6, 2020 at 19:50
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Ok got it. Thnakyou very much for nice explanation. Commented Nov 6, 2020 at 19:54
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I'm sorry, but this answer isn't quite accurate. The larger of the two caps is (probably) for energy storage, while the smaller one is (probably) for noise suppression. The 0.1uF cap will have a lower ESR which makes it better for noise suppression; the 100uF is able to store more energy. Two different objectives, two different capacitors.– SeamusCommented Nov 7, 2020 at 0:40