[simpits-tech] RC Timer delay

[Ross Hutton]

 --- Stig Joergensen <stig.joergensen@clearsky.dk>
wrote: > Hi Gang,
> 
> I need some help here. I need to calculate the time
> for RC (resistor
> -Capitor) delay circut. I know the formula is t =
> r*c, but what are the
> units?

(time constant)seconds = ohms * farads

> more specific, consider the following :
> 
> strobe----|
>         __|__
>          cap
>         _____
>           |
>           |----- out
>           |
>          | |
>          |r|
>          |_|
>           |
> gnd-------|
> 
> 
> when stobe goes high, out will go high almost at the
> same time, but what
> should the walues (r and c) be for out to go low,
> say 5 ms after strobe
> drops to low again?

When the strobe goes high in this circuit the output
will go high immediately but will start to decay to
zero all by itself (as the capacitor charges) even if
the strobe is still high.

=====
--
Ross

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