Article View: sci.electronics
Article #3353Re: 555 IC Timer help needed
From: Vaso Bovan
Date: Sat, 07 Oct 1989 03:54
Date: Sat, 07 Oct 1989 03:54
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In article <3356@ccnysci.UUCP> sukenick@ccnysci.UUCP (SYG) writes: > >Be very careful with equations: I've seen different equations for 555's, >duty cycles, frequencies, etc. depending upon the manufacturer. >Also, some will work even after pin 7 is shorted to pin 8, others >will blow out immediately if the resistance is lower than 1k or 200 ohms. I haven't been following this thread, so I don't know if this has been mentioned: All 555 timers are not made the same. For instance, pin 6 overrides pin 2 for the National LM555H, but pin 2 overrides pin 6 for the Signetics NE555V. This is covered in a short note: "Bistable Action of 555 Varies with Manufacturer", originally published in Electronics magazine (date unknown) and reprinted in "Design Techniques for Electronics Engineers," McGraw-Hill 1977, pg 32.
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!apple!mips!vaso From: vaso@mips.COM (Vaso Bovan) Newsgroups: sci.electronics Subject: Re: 555 IC Timer help needed Summary: Differences among manufacturers Message-ID: <29060@buckaroo.mips.COM> Date: 7 Oct 89 03:54:00 GMT References: <169@uwm.edu> <568@limbic.UUCP> <3356@ccnysci.UUCP> Reply-To: vaso@mips.COM (Vaso Bovan) Organization: MIPS Computer Systems, Sunnyvale, CA Lines: 14