From: Spehro Pefhany
Subject: Re: Flash A String Of LED's
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Date: Thu, 28 Nov 2002 14:10:51 GMT
NNTP-Posting-Date: Thu, 28 Nov 2002 09:10:51 EST
On Thu, 28 Nov 2002 10:04:45 +0000, the renowned Terry Pinnell
>>I'm interested in the circuit you suggested but can't make out what you
>>drew. Could you repost a .gif or something more readable?
>I'm experimenting with it, and have posted my schematic at
>I've not had a chance to breadboard it yet. And so far my attempts at
>simulation have been erratic, with great variation depending on choice
>of both PNP and NPN transistor types. So I hope Spehro will confirm I
>have the circuit drawn correctly
Yes, but there 220uF should be more like 22uF, as the OP indicated.
Vf of the LEDs is around 1.6V.
Given the lower capacitor value, you might want to try increasing
the 220R to 1K and reducing the 1uF to 0.1. Probably not your
situation, but I've seen others ;-) mistakenly use eg. 1.5 milliohms
in Spice rather than 1.5M ohm, because of the way the default
"it's the network..." "The Journey is the reward"
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