Re: 555 Timer Question
- From: "semaj" <semajx7@xxxxxxxxx>
- Date: 26 Jan 2006 13:49:27 -0800
Thanks for your answer. It's hard to explain. Something outside the
bounds of known science.
Bob Monsen wrote:
> On Thu, 05 Jan 2006 11:54:03 -0800, semaj wrote:
>
> > One final question: If the coil on the relay is something other than
> > 400 ohms resistance, how does that change the values of other
> > components, if at all? As always, thanks for your time.
> >
>
> If the relay resistance goes below about 50 ohms, you'll need a smaller
> resistor between the 555 and the NPN's base. The problem is that if the
> relay wants too much current, and the base current isn't large enough to
> pull up Vbe and saturate the transistor, the relay may not close.
>
> What are you timing?
>
> --
> Regards,
> Bob Monsen
>
> "I am turned into a sort of machine for observing facts and grinding
> out conclusions."
> -- Charles Darwin
.
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- From: semaj
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- From: Bob Monsen
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