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Topic: timing and decoupling (Read 1 time) previous topic - next topic

dhenry

Quote
To see if the start-up delay is proportional to the size of that capacitor.


Not really. Decoupling requires fast capacitors. Large electrolytic capacitors are not fast at all.

Grumpy_Mike

Good quality decoupling requires both large and small capacitors.

fungus


Quote
To see if the start-up delay is proportional to the size of that capacitor.


Not really. Decoupling requires fast capacitors. Large electrolytic capacitors are not fast at all.



I never said they were. I'm wondering if the 5V line is taking a while to rise at power-on because of that huge capacitor.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

dhenry

That's unlikely the problem: even at 1000u, to generate a time constant of even fractions of a second requires output impendance improbably high for any power supply / regulator.

The issue here is likely something else. For example I have a crystal oscillator with Rf that takes 5 - 7 seconds to start, longer in a clean environment.

As to decoupling, many people confuse bulk decoupling with (local) decoupling. They are so different that what works for one almost surely don't work for the other.

pwillard

Once again, we see why Fritzing is not the tool used by engineers to convey designs and concepts.  No offense intended,  but it kinda falls flat in the clarity department..  I understand you are new...  so i'm trying not to sound like a jerk... but that drawing  really did not really lift any fog, at  least for me.

True schematics are how ideas and solutions are shared.   Worth learning about.

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