pokietech34331 Posted August 1, 2011 Share Posted August 1, 2011 Hi E1,I have a few dc lor modules and this year I want them to run LED strips. Problem is the strips are common +ve, and have R,G,B as -ve. I have put all the modules into plastic boxes and use female rca connectors with the centre as +ve. All the led's I use have a rectifier at the begining of the string just in case I reversed the polarity on one of the rca plugs.My question is can I still plug the ribbons into the modules +ve to +ve and -ve to -ve and they would still fade,shimmer ect?many thanksDavid Link to comment Share on other sites More sharing options...
Steven Posted August 2, 2011 Share Posted August 2, 2011 Yes, they will work fine. The rectifiers are overkill, but at 12V, they won't make much of a difference. The LEDs themselves are diodes, so nothing will break if you connect them backwards, they just won't light until you connect them correctly.When you have some spare time, I would remove the rectifiers, because at this point they are just one more thing that could go wrong. Link to comment Share on other sites More sharing options...
pokietech34331 Posted August 3, 2011 Author Share Posted August 3, 2011 Steven wrote:Yes, they will work fine. The rectifiers are overkill, but at 12V, they won't make much of a difference. The LEDs themselves are diodes, so nothing will break if you connect them backwards, they just won't light until you connect them correctly.When you have some spare time, I would remove the rectifiers, because at this point they are just one more thing that could go wrong.Thanks Steve ,But dont forget that the led's are common +ve therefore only 1 +ve output from the module is used and the other 3 are -ve or common to all points on the module. This means to me that only 1 colour would light up I think.cheersDavid Link to comment Share on other sites More sharing options...
Greg Young Posted August 3, 2011 Share Posted August 3, 2011 Steven wrote: Yes, they will work fine. The rectifiers are overkill, but at 12V, they won't make much of a difference. The LEDs themselves are diodes, so nothing will break if you connect them backwards, they just won't light until you connect them correctly.When you have some spare time, I would remove the rectifiers, because at this point they are just one more thing that could go wrong.Thta's initially what I thought too Steven, but when repairing a faulty 1/2 wave string, (for a sealed, socketed LED that had failed) I found hooking up the replacement LED that it would burn out if connected in line more than a second or two with reverse polarity. I thought it was a fluke so tested it twice more, and each time the replacement LED burned out.Now I simply use test leads, and if the string doesn't come on immediately when powered up, I immediately remove the leads, reverse the orientation of the socketed LED, and reapply the power.Once assurred the string is functional again, I solder and heat shrink the new one in place. Link to comment Share on other sites More sharing options...
Steven Posted August 3, 2011 Share Posted August 3, 2011 pokietech34331 wrote: But dont forget that the led's are common +ve therefore only 1 +ve output from the module is used and the other 3 are -ve or common to all points on the module.The CMB-16D LOR DC modules use common positive. If you look closely at the CMB-16D circuit board, you will notice that the positive leads from all positive channels connect directly to the positive power input. The negative leads connect to the power MOSFETs, which then connect to the negative power input.In other words, the DC controllers use a common +V, just like your LEDs. Link to comment Share on other sites More sharing options...
pokietech34331 Posted August 4, 2011 Author Share Posted August 4, 2011 Thanks heaps Steven. Will go and try them out on the weekend.CheersDavid Link to comment Share on other sites More sharing options...
Max-Paul Posted August 4, 2011 Share Posted August 4, 2011 Greg,In your case you have all of the LED in the forward conduction except for the one LED. So, you will have almost full applied voltage across that one LED. Most LED have a reverse voltage ratting of about 6 volts or just a mite bit less. This is the reason that the one LED is failing. You are punching through the PN junction and it becomes a short not semi conductor any more. I built a pin wheel with each leg having 8 led running the length. Of the 64 LED I put in, I messed up and put one in backwards. Was wondering why 7 LED were real bright and one was not lit up. I had effectively applied 24VDC across that one LED. I have also had a few LED installed properly but it would only light up about 50% compared to the others. Replaced that one and all was good. that was cause I mixed supplier of my LEDs and one guys need a wee bit more voltage to get same current flow. Link to comment Share on other sites More sharing options...
Greg Young Posted August 4, 2011 Share Posted August 4, 2011 That makes sense Max, thanks! Link to comment Share on other sites More sharing options...
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