Can You Identify These 2 Parts? (See Pics)

Discussion in 'The Projects Forum' started by jwilli, Jul 27, 2009.

  1. jwilli

    Thread Starter Active Member

    Apr 21, 2009
    42
    0
    Here's what happened-

    I ordered 8 cheap panel meters from China to measure DC v. Three of them work fine but the other 5 are configured for something else on the board (I think AC v). Anyway, Instead of mailing these stupid meters all the way back to China, I think it would be easier to convert the board to measure DC v myself.

    So, what I did is compare one of the working meters to the non-working meters and started resoldering, etc. to make the boards match up.

    The boards that are not working are missing some parts that the boards that DO work have, and I can not identify 2 of them.

    One of them is shaped like a half circle with 3 leads coming off. The board labels each lead as "E", "C" and "B" and the part is labled "3198".

    The other part looks like a somewhat larger resistor and the board labels it as "22mH".

    Here are the pictures:

    [​IMG]

    This first picture is of the 2 parts that are missing on the non-working boards.

    And here is the picture of how the board labels these parts on the boards where they are missing:

    [​IMG]

    I'm sure some of you could identify these from a mile away.... I'm just not sure what they are so I can go and order them myself and *hopefully* get these things working!
     
  2. ELECTRONERD

    Senior Member

    May 26, 2009
    1,146
    16
    The part on the left is a 22μH Inductor and the part on the right is a 2N3198 transistor.
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The inductor is correct, but it's a stretch to identifying the transistor. A 2N3198 is a 75 watt transistor, which is hard to get in TO-92.

    The transistor is going to have a prefix of something like 2SC or 2SD. The 2SC3198 is somewhat likely, as it is a switch and comes in TO-92.
     
  4. jwilli

    Thread Starter Active Member

    Apr 21, 2009
    42
    0
    Thanks for the help! :) Got to love these forums! I knew someone would be able to spot them right off the bat...

    Thanks again guys, I'll go ahead and order these parts and see what happens.
     
  5. Jack_K

    Active Member

    May 13, 2009
    115
    0
    It looks like it's labeled 22 millihenries, not 22 microhenries. That seems a more likely value for a switching circuit.

    Jack
     
  6. DumboFixer

    Active Member

    Feb 10, 2009
    219
    34
    Could the transistor be a KTC3198 which is an NPN transistor for general purpose and switching applications ?
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Any TO-92 transistor with those 4 digits might be the one. A 2N2222 might work fine, for that matter. Any NPN switch will probably work. Part of the fun of guesswork.
     
  8. jwilli

    Thread Starter Active Member

    Apr 21, 2009
    42
    0
    Geez... I can't find anyone selling a 2SC3198, 2SD3198 or even a KTC3198 ANYWHERE! I checked out Mouser, Digikey, Newark and more...

    Anyone have any suggestions?
     
  9. Jack_K

    Active Member

    May 13, 2009
    115
    0
    Probably any NPN. Try a 2N3904. Watch out for the pin labeling. Some transistors are different.

    Jack
     
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