The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
Subject: Re: Flash A String Of LED's
X-Newsreader: Microsoft Outlook Express 5.00.3018.1300
NNTP-Posting-Date: Tue, 26 Nov 2002 20:00:27 CST
Organization: Prodigy Internet http://www.prodigy.com
Date: Wed, 27 Nov 2002 02:00:27 GMT
Some additional info.
Capacitor size is 25 ufd.. Measured current is .1 ma. at start of charge
dropping to about .05 ma. after about 2 seconds. The source is the secondary
of a small transformer half wave rectified. The transformer is part of a
small inverter circuit I put together with ideas from this and other
electronics newsgroups. The germanium transistor I used allows oscillation
with the .6 volt source I'm using. I've done some testing and the charge
developed on the 25 ufd. cap. produces a pretty good visual effect even
though the discharge rate is quite rapid. From other previous
recommendations, it would be nice to get my hands on a few of the old
Shockley diodes - it seems like they would be perfect for this application -
nice and simple.
"HuMike" wrote in message
> O.K., another LED flasher question. Here's my situation. I've got a really
> low current source capable of charging a capacitor to 12-15 volts in
> 4 seconds. I'd like to dump this charge across a string of 3-4 LED's and
> current limit resistor whenever the capacitor builds back up to that 12-15
> volt level. Is this possible with a handful of discrete parts? I know
> digital IC's would be the way to go but it seems overkill for the
> application. Thoughts appreciated.
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup