Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!gatech!bloom-beacon!eru!luth!sunic!tut!santra!saha.hut.fi!c37189h
From: c37189h@saha.hut.fi (Suomalainen Harri Olavi)
Newsgroups: sci.electronics
Subject: Re: 555 IC Timer help needed
Message-ID: <25513@santra.UUCP>
Date: 26 Sep 89 07:45:38 GMT
References: <169@uwm.edu> <568@limbic.UUCP>
Sender: news@santra.UUCP
Reply-To: c37189h@saha.hut.fi (Suomalainen Harri Olavi)
Organization: Helsinki University of Technology, Finland
Lines: 14

In article <568@limbic.UUCP> gil@limbic.UUCP (Gil Kloepfer Jr.) writes:
>I've read it is unwise to make R1 any smaller than 1K ohm.  

You're absolutely rigth about that: Pin #7 is a collector of an internal
transistor while the emitter is connected to ground. With too small a resistance
between pin #7 and positive supply rail the transistor will certainly get
damaged!

I believe R2 could be equal to 0 ohms without any damage to the chip.
At leats according to the internal connection diagram I've got no harm
should be done nor should it affect harmfully to working of 555 chip.
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