Article View: sci.electronics
Article #822Re: How can I turn on this bulb with TTL?
From: John DeArmond
Date: Sun, 16 Jul 1989 01:57
Date: Sun, 16 Jul 1989 01:57
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In article <3868@phri.UUCP> roy@phri.UUCP (Roy Smith) writes: > > The problem is that TTL can sink current, but not source it. With >TTL you really have to think current sinks instead of voltage sources. For >example, the typical circuit to light an LED: To clear up a small point. Only open collector devices do not supply current in the high state. All other TTL supplies relatively high current through a totem-pole output arrangement - it must in order to charge circuit capacitance and achieve high slew rates. My TTL book from National shows that a typical gate (7404 hex inverter to be exact) can supply 35 ma in the high state. Not a lot but still enough to work with. -- John De Armond, WD4OQC | Manual? ... What manual ?!? Sales Technologies, Inc. Atlanta, GA | This is Unix, My son, You ...!gatech!stiatl!john **I am the NRA** | just GOTTA Know!!!
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!gatech!emory!stiatl!john From: john@stiatl.UUCP (John DeArmond) Newsgroups: sci.electronics Subject: Re: How can I turn on this bulb with TTL? Keywords: NPN, TTL, bulb, 12 volts, bias Message-ID: <5841@stiatl.UUCP> Date: 16 Jul 89 01:57:55 GMT References: <4363@merlin.usc.edu> <3868@phri.UUCP> Reply-To: john@stiatl.UUCP (John DeArmond) Distribution: na Organization: Sales Technologies Inc., "The Procedure IS the product" Lines: 18