transistor help

Discussion in 'The Projects Forum' started by markosillypig, Dec 5, 2013.

  1. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
    184
    0
    hi every one
    my new project is to make a bigger temperature led scale using a
    0.56 " Digital Display Red LED item from ebay


    http://www.ebay.co.uk/itm/190898617176?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
    problem i have is that i was going to use an uln2803 for the second set of led's but looking at the schematic of the segment led it it's outputs are 3 vcc and the rest is -vcc the uln2803 works on a + not a - so what chip could i use to make this work
    cheers
    marko
     
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,869
    1,393
    The item you linked to is a complete temperature module. It has its own thermistor sensor and its own display. There is nothing to build; just connect power and ground and it works.
     
  3. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
    184
    0
    i want to make a bigger one using led strips
     
  4. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,869
    1,393
    Then you need an electrical design. The design will need to include a temperature sensor (thermistor, or IC like the LM34), a means of converting the sensor output to a usable format, a display driver, and a display.
     
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