Matching PNP and NPN transistor help

Discussion in 'General Electronics Chat' started by danger, Oct 3, 2010.

  1. danger

    Thread Starter New Member

    Sep 5, 2010
    I have a BC213 PNP transistor manufactured by Micro Electronics. I need to match this with a BC183 with a 5% tolerance for a project I'm working on. In my investigation I have found that the BC213 is considerably harder to come by than the BC183 even though they are both considered obsolete. So I'd rather not hunt down a different BC213.

    My question is... in order to match the 2 transistors within a 5% tolerance would any BC183 do? Or do I need to find one manufactured by Micro Electronics as well. I have taken a peek at the datasheets for the ME versus the Fairchild Semi(which seems to be available some places). But with my limited knowledge I can't seem to tell whether or not they match up good enough. I'm not really sure what to look for in the datasheets.

    Another question maybe simpler... when matching a PNP and NPN transistor within a 5% tolerance, what parameters in their specifications are most critical?
  2. romel_emperado

    New Member

    Jul 23, 2009
    hi, i dont know whats the answer of your question but i post here in your thread to be notified if someone will post here the idea... thanks man...
  3. t06afre

    AAC Fanatic!

    May 11, 2009
  4. Wendy


    Mar 24, 2008
    Datasheets are your friend. Generally they will include the complementary transistor part number for the parts whose specs are listed. So will some parts houses. For example, a 2N2222A is complementary to the 2N2907A.

    Matching to 5% tolerance is not likely. Even a transistor family will not fall within 5% tolerance with the same part numbers, transistors naturally have wide variations, especially with the gain spec (hfe, beta).

    Where they are matched is power dissipation, internal resistances, and other factors.

    This is why using negative feedback is pretty important in transistor design is so important, to bring the specs under control.

    Since you haven't included a schematic there isn't really too much we can do to help with specifics.
  5. marshallf3

    Well-Known Member

    Jul 26, 2010
    Two forms of matched -

    1) Two transistors of the same part # that come very close to each other in gain

    2) Two transistors of different polarity that have similar voltage, current, power and gain characteristics. Usually referred to as a complimentary pair.

    In case 1 it's usually a matter of testing them on your own, in case 2 they'll have the voltage, current and power cojnsiderations pretty closely matched if not identical and the gain will generally fall within 10% - 20% of each other.

    In your case I'd think a 2N3904 & 2N3906 would make good substitutes for the transistors in question, they're similar in gain and equal or better in most specs.
    Last edited: Oct 3, 2010
  6. danger

    Thread Starter New Member

    Sep 5, 2010
    Thank you so much for the help!

    This is a link to the datasheet for the part I have already. The BC213. The link on the page that prompts for download simply enlarges the sheet. So no worries clicking on it...

    Here is a link to the Fairchild Semiconductor BC183 that I'm hoping is compatable...

    And finally, the BC183 made by Micro Electronics, that was intended to be paired with the one I have, but is proving very difficult to source.

    Now, I don't EXPECT anyone to have a go at figuring this out for me. However, I thought I'd post these just in case someone has the time and is feeling extra helpful. Basically I would like to know if the Fairchild 183 is compatable with my ME 213.
  7. gootee

    Senior Member

    Apr 24, 2007
    So it sounds like maybe you want to set up a test circuit for your BC213 and measure the gain (or whatever you need to match) and then set up a complimentary test circuit for BC183 transistors and test a number of them until you find one that has a gain (or whatever you need to match) within 5% of the BC213's gain, under similar but complimentary voltage/current conditions.

    Edit: Just saw your last post. Haven't looked at your datasheets. But even if you find what the datasheets say are a complimentary pair, you would probably still need to hand-match any _particular_ pair, to get within 5%.
  8. danger

    Thread Starter New Member

    Sep 5, 2010
    By the way, I am trying my best to learn from what you guys have already posted. It has been very helpful in understanding this further.
  9. Wendy


    Mar 24, 2008
    Many DVMs have a Hfe test port for both NPNs and PNPs. This would be very useful for what you're trying to do.