npn transistors

Discussion in 'General Electronics Chat' started by duxbuz, Dec 4, 2014.

  1. duxbuz

    Thread Starter Member

    Feb 23, 2014
    133
    0
    Hi

    Can anyone tell me why the main difference is between these 2 transistors:

    http://cpc.farnell.com/on-semiconductor/mps2222a/transistor-npn-to-92/dp/SC06675?Ntt=sc06675

    http://cpc.farnell.com/on-semiconductor/p2n2222ag/transistor-npn-to-92/dp/SC12549?Ntt=P2N2222A


    I know that's an open ended question. I am trying to work out why I would have bought the mps2222a, I can only imagine I was buying 2222a transistors and I bought them to cover the bases as I don't rightly know enough to make a proper informed purchase when it comes to components.

    I think at the time I was reading about using transistors to switch small motors on with microcontroller pins.

    Are the mps2222a transistors going to perform the same?

    The mps2222a is named a general purpose transistor, and the pins seem to be numbered different, but it is still npn not pnp.

    The psn2222a is named and amplifier transistor.

    Does that mean the mps2222a has no amplification characteristics.

    Thanks
     
  2. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    Every transistor can act as amplifier and switch. I would buy MPS because it has greater Hfe while having the rest of the specifications same as other one.But still it all depends on the circuit design and how much current it needs to pass and how much current is at the base.
     
  3. duxbuz

    Thread Starter Member

    Feb 23, 2014
    133
    0
    Thanks

    base current would be up to 40 mA (milliamps) for microcontroller pin I think.

    The Hfe looks the same to my untrained eye.

    Is there a reason the pins are reversed?
     
  4. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    Pinout is different because it isn't standardized only the package is.If you apply 1mA on transistors base you will get amplification of 100mA.What kind of load you want to drive?
     
  5. duxbuz

    Thread Starter Member

    Feb 23, 2014
    133
    0
    Thanks for your help

    The motor was bought from a supplier with no real specification other than
    voltage 1.5 to 4.5v, current 0.083 to 0.41A

    so 83mA min to 410mA

    I am not going down the 'I thought the transistor was in saturation' route again right now, as I have not had my electronics head on for months!

    I never really reached total clarity the last time I asked that one!
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,505
    2,367
    Have you looked at something like the 2n7000? designed for this type of application.
    Or IRL520/530 for higher current.
    Max.
     
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