Article View: sci.electronics
Article #18271Re: 555 timer duty cycle
From: Wolfgang Rupprecht
Date: Tue, 24 Nov 1987 04:45
Date: Tue, 24 Nov 1987 04:45
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In article <9376@shemp.UCLA.EDU> khayo@MATH.UCLA.EDU (Erazm J. Behr) writes: >Is there any way to wire the 555 to get an "on" time of >less than 50% of the cycle? (I know, "just add an inverter" - >but I'd like to know if it can be done without adding extra >active parts). Sorry for this, I'm sure the answer is in the >library somewhere ...... 8-O 1) Don't use the open collector pull down to discharge the capacitor. 2) Run the charging resistor to Q. (you now hve a 50% duty cycle osc.) 3) To make the charge faster than the discharge add a diode with series-resistor in parrallel to the charging resistor. -- Wolfgang Rupprecht UUCP: mit-eddie!mgm.mit.edu!wolfgang (or) mirror!mit-mgm!wolfgang ARPA: wolfgang@mgm.mit.edu (IP addr 18.82.0.114)
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!mnetor!uunet!husc6!bloom-beacon!mgm.mit.edu!wolfgang From: wolfgang@mgm.mit.edu (Wolfgang Rupprecht) Newsgroups: sci.electronics Subject: Re: 555 timer duty cycle Message-ID: <1876@bloom-beacon.MIT.EDU> Date: Mon, 23-Nov-87 23:45:23 EST Article-I.D.: bloom-be.1876 Posted: Mon Nov 23 23:45:23 1987 Date-Received: Thu, 26-Nov-87 21:53:10 EST References: <9376@shemp.UCLA.EDU> Sender: daemon@bloom-beacon.MIT.EDU Reply-To: wolfgang@mgm.mit.edu (Wolfgang Rupprecht) Organization: Independent Software Consultant Lines: 16