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Re: 555 Calculator

Subject: Re: 555 Calculator
From: Fred Bloggs
Date: Sat, 22 Apr 2006 16:49:19 GMT
Newsgroups: sci.electronics.basics, sci.electronics.design, sci.electronics.misc, sci.electronics.components

Google, "NE555 calculator", second result:
http://www.daycounter.com/Calculators/NE555-Calculator.phtml

That does what you're wanting. It assumes a practical value for one of the components and calculates the other values from the freq and DC input.

I suppose the more intelligent way to use that calculator is to enter duty cycles that are arbitarily close to and above but not exactly equal 50%. Of course, you wouldn't know to do this if all you've ever done is use calculators. Entering 50.3% , 1KHz, and C=0.001u, values obtained with some fairly rough insight into 555 operation, returns RA=8.64K and RB=716K- not std values according to my other formula derived mysteriously from additional applications insight, almost as good as, but a lot less fun than, the manual method.


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