Name that cap...

[Gordon JC Pearce]

Tony Duell wrote:
>>Well - the spec for the LS121 is pretty well-known.  Someone with more 
> 
> 
> IIRC, the pulse width is something like 0.7*R*C
> 
> 
>>caffeine and inclination than I might well look up the datasheet and 
>>work out what the value ought to be.  It looks like it says "270" 
>>overscribbled with "220" to me - what units I don't know.  Try 220nF. 
>>If that doesn't work, try 220pF.  You'll be in the ballpark with one of 
>>those.
> 
> 
> Assuming R is within the recomended range for the IC, you are not going 
> to get a 5.5us pulse (which sounds about right) with a 270nF cap. 270pF 
> could well be right.

Yeah.  Brain fart, brought on by lack of decent caffeine.

Gordon.