NPN transistor connections which end is the collector

Discussion in 'General Electronics Chat' started by Klubowy, Jun 6, 2016.

  1. Klubowy

    Thread Starter New Member

    Apr 30, 2016
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    Hi I'm just learning the basics in electronics and I'm a bit confused. Some sources say that the transistor when facing the flat side has the E B C in that order from left to right. Others maintain that when read from left to right it's C B E. Now which end is the collector and which is the emitter. I hope I didn't make it too confusing.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Refer to the data sheet.;)
    Not all conform to below diag.
    [​IMG]
     
    Last edited: Jun 6, 2016
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  3. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    Assuming we are talking about the TO-92 package for small signal bipolar transistors, there are 6 possible arrangements of three pin signals and somewhere there is a transistor for almost every one. There is no standard. Two of the arrangements are much more popular than others, but there is no standard. "When facing the flat side", E B C and E C B are the two most popular.

    Be very careful when reading datasheets. Most datasheets indicate the pinout with the part viewed from the top, but National Semiconductor (and others) often show the pinout when viewed from the bottom.

    ak
     
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  4. WBahn

    Moderator

    Mar 31, 2012
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    Strongly ditto AK's response.

    Always refer to the data sheet for THAT part from THAT manufacturer (though most manufacturers will conform to the same pinout for the same nominal part number, this isn't guaranteed) and always look carefully at the pinout diagram to see if it is as view from the top or the bottom.
     
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  5. Klubowy

    Thread Starter New Member

    Apr 30, 2016
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    I read somewhere this trick to memorise the pins. Its a sentence: Enjoy British Columbia E B C (when facing the flat side of the transistor)
     
  6. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Does not work with all NPN's.
    upload_2016-6-7_7-15-58.png

    That is the BC546 and many others. Checking the datasheet is the only way.

    John
     
  7. WBahn

    Moderator

    Mar 31, 2012
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    That would only be useful if all transistors used the same pinout. As AK pointed out, there are six possible combinations and there are transistors out there that use each of them.
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Created by someone in Vancouver!;)
    Max.
     
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  9. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Always check the datasheet as the pinout can be different for transistors, even with the same number, but an other manufacturer.
    Did you ever think about the pinout combinations?
    Adding fet connections you get quite a list:

    Transistor_pinout.png

    Bertus
     
  10. wayneh

    Expert

    Sep 9, 2010
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    One of my pet peeves is when the datasheet does not use a "3D" view for the pinout, so that it's ambiguous whether to view from above or below, or from front or back. Even if it tells you, it's still so much easier to get the pinout right when you can see the whole part in your head.
     
  11. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    I can't elevate it to a peeve. So long as the B is in the center, which is not affected by the perspective, if it doesn't work, I use the "USB-protocol." That is, remove it and turn it around.

    John
     
  12. ian field

    Distinguished Member

    Oct 27, 2012
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    Any device worth using will have easy to find data somewhere online - failing that; the base/emitter junction will behave like a Zener somewhere around 5 - 8V. If the collector/base junction does that - its either a highly esoteric RF device, or scrap.
     
  13. hp1729

    Well-Known Member

    Nov 23, 2015
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    All the comments so far are good. You need to get a data sheet for the specific transistor you have. There a lot of places on the internet to get datasheets. My favorite is www.alldatasheet.com.
     
  14. ian field

    Distinguished Member

    Oct 27, 2012
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    Its possible to make a few generalisations about leadout order - most Asian transistors have the sequence; BCE, most European types are; BCE, but that can be either way round with the flat side of a TO92 facing down. American transistors can be either format, but mostly EBC.

    TO220 and the several variants of TO3P are BCE, the TO126 is back to front relative to the heatsink .

    RF transistors often depart from these formats - sometimes the emitter is the middle pin.
     
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