On Thursday, January 19, 2012 07:27:22 PM Viesturs Lācis did opine: > Hello, folks! > > I would appreciate some advice or insights, what am I doing wrong. > > What I want to do is to switch on and off a power to laser engraver > diode. It needs 12 VDC supply and it consumes ~1 A currrent. > > Here is schematics of what I currently have: > http://picpaste.com/DSCF6164-vX7heUEq.jpg > > The problem is that it is not working: > Voltmeter was showing +12 VDC on both leads, going to laser module all > the time, regardless if I had turned the output pin "true" or not. > > First of all I am interested, if the scheme is actually correct. From what you say, the opto's led isn't being sufficiently excited to turn on the darlington photodetector. Are you sure that with the applied voltages, that the 1k in series with the driver led is sufficient to properly excite it? If that is a 5 volt circuit, the 1k will only allow maybe 2.2 milliamps, not enough in some cases. Try a 330 ohm, on down to 120 maybe, as the limiting resistor. 120 should give a bit over 20 ma of led drive. If that doesn't do it, I'd suspect the device might be defective.
> Thanks! > > Viesturs > > ------------------------------------------------------------------------ > ------ Keep Your Developer Skills Current with LearnDevNow! > The most comprehensive online learning library for Microsoft developers > is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, > Metro Style Apps, more. Free future releases when you subscribe now! > http://p.sf.net/sfu/learndevnow-d2d > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users 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) My web page: <http://coyoteden.dyndns-free.com:85/gene> There is always something new out of Africa. -- Gaius Plinius Secundus ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
