pipeorgan Posted February 23, 2008 Report Share Posted February 23, 2008 In using the R4 DOUT with ULN2803's as driver boards, how much load can the board support from the ULN2803's to the output headers? Typical pipe organ valve magnets range from 90 to 50 ohms. The common ground supports multiple valves on (up to eight) all on at once. Are the output traces designed to handle this? Quote Link to comment Share on other sites More sharing options...
stryd_one Posted February 23, 2008 Report Share Posted February 23, 2008 Welcome aboard pipeorgan. I've deleted your crosspost ... you only need to ask once :) I'm not sure about the answer but I think that if you use the Search you'll find it. Quote Link to comment Share on other sites More sharing options...
Trevor Posted February 23, 2008 Report Share Posted February 23, 2008 The ULN2803 is plenty to drive a 50ohm magnet Quote Link to comment Share on other sites More sharing options...
pipeorgan Posted February 24, 2008 Author Report Share Posted February 24, 2008 The ULN2803 is plenty to drive a 50ohm magnetYes the ULN's will do fine, its the traces on the DOUT board from the ULN2803 output to the output header that concerns me (only when using ULN2803's) as they have to carry the load of an electo-maganet. On various pipe organ driver boards that incorporate ULN2803's, the traces and ground are beefed up.Pipe valve example: http://www.petersonemp.com/products/pdf/Seriesii.pdf (pdf)Thanks. Quote Link to comment Share on other sites More sharing options...
sparx Posted February 24, 2008 Report Share Posted February 24, 2008 I strongly suspect that it will be OK, assuming 12V and using Ohms law, V/R = 12/50 = 0.24 or 240mA. The traces should hold.If not, post back here and then we all know!Regards and good luck!Sparx Quote Link to comment Share on other sites More sharing options...
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