Does anyone know why my LEDs occur error?

Discussion in 'General' started by suli, Jun 22, 2017.

  1. Hello~all,thanks for taking time to read my thread.I'm a student majoring in circuit and I meet some troubles now.I hope I came the right forum and you can help me out.
    I don't know how to state my problems shortly and please allow me state my troubles clearly.
    I used LPC103 and I controlled ten road LED by using IO port of ten road.The source of every road led is 12V while it connected the resistance of 680 ohm and four LEDs. The program control the base high/low level of NPN ( this one) triodes to realize that the LEDs can open and close.However,some LEDs send weak light and they can’t be closed.I don’t know what reason lead to this problems ! Because of some special request,here has four boards which two boards belongs to signal floors and the up and bottom is cables and covers. Do you know how to solve this problems?Can you?
    I am grateful for you advice. Thanks a lot!
    PS: Please look at the picture I have upload and it will help you understand my troubles
    Have a nice day~

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