---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 06/16/14: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:06 AM - Re: LED Ghosting (Robert L. Nuckolls, III) 2. 08:46 AM - Re: LED Ghosting (donjohnston) 3. 12:43 PM - Re: LED Ghosting (donjohnston) 4. 06:02 PM - Re: Re: LED Ghosting (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:06:15 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: LED Ghosting At 12:57 PM 6/15/2014, you wrote: > >I've built a Master Warning Panel using LEDs for things like boost >pump on, starter engaged, pitot heat on, etc. I'm using Eric's >EGRAVR dimmer to control the brightness. Everything works great. > >http://www.velocity-xl.com/blog/wp-content/uploads/2013/08/2013-08-14-IMG_20130814_191418_518.jpg > >Except the engine analyzer (low oil pressure) alarm. > >That line is supposed to go to ground when an alarm condition >occurs. But the LED for that warning is always slightly lit. The >engine analyzer people said it was designed for incandescent and to >put a 1.5k resistor across the LED. Wrong place for the resistor. There is a resistor X in series with the LED to bias it up to run on the 14V supply. Resistor Z is used to make the diode/X string emulate an incandescent bulb. Try 1000 ohms at Z. Emacs! Bob . . . ________________________________ Message 2 _____________________________________ Time: 08:46:36 AM PST US Subject: AeroElectric-List: Re: LED Ghosting From: "donjohnston" nuckolls.bob(at)aeroelect wrote: > > Wrong place for the resistor. There is a resistor X in > series with the LED to bias it up to run on the > 14V supply. Resistor Z is used to make the diode/X > string emulate an incandescent bulb. Try 1000 ohms > at Z. > > [img]cid:7.1.0.9.0.20140616075849.01f3d938@aeroelectric.com.0[/img] > > > > Bob . . . Well that would make my life a gazillion times easier! It makes sense too. I'll give it a try. Thanks! Read this topic online here: http://forums.matronics.com/viewtopic.php?p=424936#424936 ________________________________ Message 3 _____________________________________ Time: 12:43:02 PM PST US Subject: AeroElectric-List: Re: LED Ghosting From: "donjohnston" Sadly, it did not help. It does eliminate the ghosting. But just like when I put the resistor across the LED, it still results in a dimmer LED overall. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=424951#424951 ________________________________ Message 4 _____________________________________ Time: 06:02:01 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: LED Ghosting At 02:41 PM 6/16/2014, you wrote: > >Sadly, it did not help. It does eliminate the ghosting. But just >like when I put the resistor across the LED, it still results in a >dimmer LED overall. Okay, was this 'output' intended to drive an incandescent lamp in the first place? The symptoms you describe suggest that it's an LED specific output and may have a resistor already built into the output. Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.