On Sun, 2 Mar 2014, Gene Heskett wrote: > Date: Sun, 2 Mar 2014 16:10:23 -0500 > From: Gene Heskett <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Subject: [Emc-users] This sparkfun opto kit, > 2 channel. Question re led polarities. > > Greetings; > > leds are something I'll have to plead less than a full understanding of. > > So, if I connect these 2 channels of this sparkfun kit such that the anode > of one is connected to the cathode of the other, effectively placing them > in parallel, add a current limiter in series with the common of one end, do > I need to also put in a reverse voltage protection diode, or will the one > that needs to light up, will light up without being shorted out by the > other polarity led across it? > > The C1G can put out sufficient currant (24 ma) but I believe its > programming jumpers cannot allow both polarities, its a one or the other > deal per data line, so I'll have to invert the signal to get the opposite > drive external to the C1G, but that doesn't seem to be a show stopper. > > The idea is to have the 2 optos outputs in totem pole for a bidirectional > drive +12 volts or 0 volts, both active on an exclusive basis into the > Gemini controller. > > The question is, do I need to polarity protect the leds in the opto > package? The pdf I downloaded on the opto package is less that informative > on this particular detail. > > Cheers, Gene > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > Genes Web page <http://geneslinuxbox.net:6309/gene> > > NOTICE: Will pay 100 USD for an HP-4815A defective but > complete probe assembly.
Back to back LEDs should work fine (usually they have a 5V max reverse voltage spec and about 1.1V forward drop so one protects the other. but back to back LEDs need a bipolar source (say 2 equal resistors for a 2.5V reference/current limit and a push pull 5V output) If you have a 5V push-pull output, another way would be to connect this output to Cathode1 and Anode2 and connect Anode1 to 5V through a resistor and Cathode2 to ground through another resistor. > > > ------------------------------------------------------------------------------ > Flow-based real-time traffic analytics software. Cisco certified tool. > Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer > Customize your own dashboards, set traffic alerts and generate reports. > Network behavioral analysis & security monitoring. All-in-one tool. > http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Flow-based real-time traffic analytics software. Cisco certified tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer Customize your own dashboards, set traffic alerts and generate reports. Network behavioral analysis & security monitoring. All-in-one tool. http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
