Hi Neil, IR LEDs have really low Vf, something like 1.1 volts at continuous rated cu= rrent, and probably still pretty low at high, pulsed current. You could eas= ily use them in series pairs. Cheers, Bob ________________________________________ From: piclist-bounces@mit.edu on behalf of Neil <= picdude3@narwani.org> Sent: Monday, October 17, 2016 10:20 PM To: Microcontroller discussion list - Public. Subject: Re: [EE] Multiple IR transmitters for better coverage? I will be powering this from a 6V wall-wart with a 5V, 500mA switching converter. I have a bunch of 9V wall warts laying around, but that's not much better. Yes series is easier, but I don't have much overhead voltage to work with. Other than just needing more resistors, is there a benefit to series for this usage? Cheers, -Neil. On 10/18/2016 12:28 AM, Harold Hallikainen wrote: > Neil, > > If you have enough voltage, it's easier to put the LEDs in series which > puts the same current through each. > > The emitter is shown at > http://www.uslinc.com/index.php?page=3Dshop.product_details&flypage=3Dfly= page.tpl&product_id=3D44&category_id=3D21&option=3Dcom_virtuemart&Itemid=3D= 106 > . It carries hearing impaired audio, visually impaired audio, and closed > captions in movie theaters. > > Harold > > > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .