12v // Seven Segment // Arduino // Max7219 // DLN2981

Discussion in 'General Electronics Chat' started by kelvinmead, Apr 23, 2013.

  1. kelvinmead

    Thread Starter Member

    May 15, 2011
    30
    0
    Hi,

    I'm building a circuit using a large 12v seven segment display (3 of) and i wish to have the counting part of the circuit done by an arduino, and the segments driven with a max7219.

    the segments are common cathode, so i can't use the easier TPIC6B595 to shift and carry the larger current.

    so i have to use a driving version of the usual ULN2803 and this brings me to a DLN2981... of which i can't seem to find a supplier with stocks on hand... so whilst i await the chip to fall on my doorstep, what alternatives can i use.

    I guess that i can drive each line singularly with a standard NPN transistor PN222A


    5V -------> 5V -------> +12V> +12V ---------------> GND
    ARDUINO > MAX7219 > NPN > SEGMENT DISPLAY > GND

    seem logical?
     
    Last edited: Apr 23, 2013
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