Path: utzoo!attcan!uunet!aplcen!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!usc!apple!snorkelwacker!bloom-beacon!athena.mit.edu!maddog
From: maddog@athena.mit.edu (Matthew J Marjanovic)
Newsgroups: sci.electronics
Subject: Re: LED brightness, colors
Message-ID: <1990Jun28.210949.19237@athena.mit.edu>
Date: 28 Jun 90 21:09:49 GMT
References: <7644@jarthur.Claremont.EDU>
Sender: news@athena.mit.edu (News system)
Reply-To: maddog@athena.mit.edu (Matthew J Marjanovic)
Distribution: na
Organization: Massachusetts Institute of Technology
Lines: 38

In article <7644@jarthur.Claremont.EDU>, rspangle@jarthur.Claremont.EDU
(Randy Spangler) writes:
|> 

|> Also, what's the easiest way to blink a high-current LED at say 2-10 Hz?
|> I've heard there's some way to do it with a 555 timer, but electronics isn't
|> my strong point.  Blinking LED's (that have the driver built in) seem to be
|> a lot dimmer than non-blinking ones.
|> 

	If you want blinking LED's pretty easy, try the LM3909 (if I 
 	  remember the number correctly) LED Flasher chip, designed for
	  just that purpose.  You can find the chip anywhere that sells
	  the standard stock of linear IC's (such as Jameco, Digi-key, etc.
	  Radio Shack may even carry it.).

	The data sheet for the chip lists a couple of pages of applications,
	  most of which will pulse a LED for years off of a single 1.5 volt
	  battery with one or two capacitors (values provided).  Most of 
	  the schemes have a higher current / lower duty cycle, which give
	  bright pulses.
	
	It couldn't be any easier (except for the blinking LED's themselves.)

|> 
|> -- 
|>  --------------------------------------------------------------------------
|> |    Randy Spangler                    |    The less things change, the    |
|> |    rspangle@jarthur.claremont.edu    |    more they remain the same      |
|>  --------------------------------------------------------------------------



____________________________________________________________________
Matt Marjanovic          | "He who has never envied the vegetable,
maddog@athena.mit.edu    |    has missed the human drama."
                         |                      -- E.M. Cioran
--------------------------------------------------------------------