Alternative transistor to BD139 I can get from Maplins

Discussion in 'The Projects Forum' started by Jake2, Apr 4, 2012.

  1. Jake2

    Thread Starter New Member

    Apr 4, 2012
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    I am doing an Arduino project. The design specifies a BD139 transistor.
    http://www.discountelectronicsstore...standard-bipolar-npn-power-transistors-bd139/

    To avoid paying £3 postage on a 50p transistor, I'd like to get this at Maplins. Unfortunately, the very nice and helpful guy at the shop says he knows all about resistors, capacitors, and diodes, but not about transistors. So he couldn't help.

    Can anyone tell me which transistor in the Maplins catalogue is equivalent to this BD139?
     
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Can you post a schematic of the intended circuit?

    I have attached the datasheet for you for the data.

    Bertus
     
  3. Jake2

    Thread Starter New Member

    Apr 4, 2012
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    I want to control a motor from the arduino. The circuit is in the "30 Arduino Project for the Evil Genius" (Pg 133, in case you have that book) - so I don't have an electronic copy of it.

    Here is another design for controlling the motor, which I could use.
    http://luckylarry.co.uk/arduino-pro...th-potentiometer-and-multiple-power-supplies/

    This one suggests a TIP120 transistor - which I also can't find at Maplins.

    Basically, I am a teacher (maths, so no knowledge of electronics) and am trying to build a prototype robot which I can then guide some students through (secondary school). So any simple design would be fine - that doesn't cost too much!
     
  4. bertus

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    Apr 5, 2008
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  5. Jake2

    Thread Starter New Member

    Apr 4, 2012
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    Thanks for that, and for the amazingly quick responses.

    The Arduino generates 5V from its pin. Should I be able to use one of these as an alternative to the BD139 and the TIP120 in the circuit? i.e. to control the current to the motor?
     
  6. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    In the show project in the link, a 1K resistor is used between the arduino pin and the base of the transistor.
    The shown alternative transistors will work with this value too.

    Bertus
     
  7. Jake2

    Thread Starter New Member

    Apr 4, 2012
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    Great.

    Thanks so much for your help.
     
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