> On Sunday 02 March 2014 18:12:42 Peter C. Wallace did opine: > > > On Sun, 2 Mar 2014, Gene Heskett wrote:
> > >> 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. > > > > > > But the i limiting R can also be in the common signal input line I'd > > > assume? Or will that common voltage drop eat my lunch? OTOH, > > > resistors in 500 packs from the shack are cheap. :) > > > > > > > Sure, one resistor is fine for the second method. Slight advantage of > > two is that the LED drives can be individualy adjusted. Wait a minute. It sounds like you are suggesting anode 1 to +5V. Cathode 1 to anode 2, with a resistor to the signal source. And cathode 2 to ground. That won't work, there is a path from +5V thru both LEDs to ground, with no current limiting resistor. That will let the smoke out of both LEDs. If you are using a single ended source, you want two limiting resistors. +5V, thru resistor 1, to anode 1. Cathode 1 to anode 2 and input signal. Cathode 2 thru resistor to ground. You can put the resistors on the inside if you want: +5 V to anode 1. Cathode 1 thru resistor to input, then another resistor from input to anode 2. Cathode 2 to ground. But you still need two resistors. If the input signal is differential, then you can hook the LEDs back-to-back, and use a single limiting resistor. -- John Kasunich [email protected] ------------------------------------------------------------------------------ Subversion Kills Productivity. Get off Subversion & Make the Move to Perforce. With Perforce, you get hassle-free workflows. Merge that actually works. Faster operations. Version large binaries. Built-in WAN optimization and the freedom to use Git, Perforce or both. Make the move to Perforce. http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
