Shift register and Dot matrix led

hello every one

I Would like to know why ceramic and electrolyte capacitors are needed between vcc and gnd for a shift register 74hc595 while controlling dot matrix led segment

thanks

thulasi

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jadew over 12 years ago

They're needed to quickly supply current. Those chips will consume current in bursts and when that happens, if you don't have the caps to supply it, your VCC line will get pulled down a bit and that's going to generate a lot of noise on the rail.
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e14 Contributor over 12 years ago in reply to jadew

Hello Razvan

Thanks for reply

why these capacitors are in parallel, what is their individual roll
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jadew over 12 years ago in reply to e14 Contributor

Hey Thulasi, you should do a google on decoupling capacitors.

There's also a wikipedia entry which seems to do a pretty good job at explaining why they're needed: Decoupling capacitor - Wikipedia, the free encyclopedia

Razvan
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e14 Contributor over 12 years ago in reply to jadew

Thanks for solution
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e14 Contributor over 12 years ago in reply to jadew

Thanks for solution
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