Reply-To: "fred bartoli"
From: "fred bartoli"
Subject: Re: Flash a string of LEDs
Date: Tue, 3 Dec 2002 14:08:01 +0100
X-Newsreader: Microsoft Outlook Express 5.00.2314.1300
Organization: Guest of ProXad - France
NNTP-Posting-Date: 03 Dec 2002 14:08:12 MET
Terry Pinnell a écrit dans le message :
> Spehro Pefhany wrote:
> >On Thu, 28 Nov 2002 15:11:27 +0000, the renowned Terry Pinnell
> > wrote:
> >>Spehro Pefhany wrote:
> >>>Yes, but there 220uF should be more like 22uF, as the OP indicated.
> >>>Vf of the LEDs is around 1.6V.
> >>Did you post an updated ASCII that I missed?
> >No, it's not really germane to the circuit in general, it will
> >just run slower with a larger cap, and I'd already mentioned it to
> >the OP privately when he e-mailed about the fixed-width font issue.
> It's a Spice issue, as it worked fine on breadboard with component
> values as per your/my circuit schematic (about 1 Hz).
> If Helmut Sennewald or Fred Bartoli see this and have the time and
> inclination, it would be educational to see how they get it simulating
> in SWCAD III and ICAP respectively. Probably too much to hope for
> anyone else with CircuitMaker.
> I scattered .IC parts around liberally, rang the changes on step
> times, and even kicked my desk, but still no regular output.
the circuit works nice... once you have settled the UIC (use initial
conditions) flag on the .TRAN line and given an initial condition of 0V for
the 22uF capacitor.
Otherwise the circuit have (with the original values) a stable state that is
found at the initial bias point calculation. Common startup problem of
oscillators with spice.
> [My regular ISP is having serious problems, so this is being sent via
> an alternative ISP using another instance of Agent. Therefore it may
> appear as a new post, rather than within the proper thread.]
> Terry Pinnell
> Hobbyist, West Sussex, UK