Re: OT. How the Dutch view our Election

On Sun, 11 May 2008 15:25:41 -0300, YD <ydtechHAT@xxxxxxxxxx> wrote:

Late at night, by candle light, John Fields
<jfields@xxxxxxxxxxxxxxxxxxxxx> penned this immortal opus:

On Sat, 10 May 2008 16:35:53 -0700 (PDT), bill.sloman@xxxxxxxx wrote:

On 10 mei, 19:06, John Fields <jfie...@xxxxxxxxxxxxxxxxxxxxx> wrote:

snip-snap>

As I said at the time the additional diode that you had to add to the
555 to make it do what the OP wanted further screwed up the already
dire temperature stability of the 555 as a timer. Since you don't
understand concepts like temperature stability, this may not appear
material to you - it certainly didn't at the time.

---
Since the resistors in the 555's reference divider are all isothermal,
the ratios between them will stay pretty constant with changes in
temperature, the result being that the timing accuracy will stay
constant within about 50ppm/C°, which is hardly what I'd call "dire"
temperature stability.


It's nice enough for most applications and can be made pretty accurate
with some tweaking. If the timing requirements are really critical
then it's time to go looking for something better (and usually
costlier).

---
You're preaching to the choir.

JF
.

Relevant Pages

  • Re: OT. How the Dutch view our Election
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  • Re: OT. How the Dutch view our Election
    ... penned this immortal opus: ... As I said at the time the additional diode that you had to add to the ... dire temperature stability of the 555 as a timer. ... the result being that the timing accuracy will stay ...
    (sci.electronics.design)
  • Re: OT. How the Dutch view our Election
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  • Re: OT. How the Dutch view our Election
    ... penned this immortal opus: ... dire temperature stability of the 555 as a timer. ... voltage regulator which helped that particular problem, ... and National stopped making it many years ago. ...
    (sci.electronics.design)