LM555 Basics

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tcbyjj

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Hello - I am new to electronics - I am a mechanical engineer . . please don't hate me . . .

Okay, I have a simple project that I can't seem to get all the numbers to jive right. I am looking to switch a simple LED / incandescent on, then off . . at ~1 second intervals...

Figured I would use a 555 timer with a variable pot . . .but I can't seem to get the right values for this .

Any help would be greatly appreciated !
 

here is a 555 tutorial website:
 
i recommend you download the data sheet for the 555. The one that i have has all the formulas you need for determining values for R1,R2 and C to achieve whatever sq wave output you want.
 
If you already built the circuit, and its not quite what you expected, maybe the capacitor is a little off or bad, happens... Oh, the first cycle is always shorter for some reason....
 
Search for SS55511.EXE A nice free program that calculates the circuit and values for at least 4 modes.
 
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