I'm looking at this IC: link here

And noticed under "typical application" a simple circuit diagram. What is the purpose of the capacitor that connects Vin directly to ground?

How does this affect the current/voltage being applied to vdd and the LED?

I have virtually no understanding of how/why capacitors are used in general. My very limited electronics experience has just about covered resistors. Would appreciate small words, and possibly somewhere to get further information (free online courses?)

  • \$\begingroup\$ sort of answers my question, though I don't understand why... \$\endgroup\$ – Zack Newsham Feb 19 '15 at 5:54

If you look at the rest of the diagram, you will see that the ground symbol is used for all of the circuit blocks. In other words, the ground symbol is the negative common wire for all of the circuit blocks.

The reason for the input capacitor is to ensure that the chip is stable and doesn't oscillate. This input capacitor (and the output capacitor) needs to be physically located close to the chip.

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  • \$\begingroup\$ So in an ideal situation the capacitors have no effect on the circuit, they are just there to maintain a constant voltage? \$\endgroup\$ – Zack Newsham Feb 19 '15 at 6:10

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