What device is this?

Discussion in 'General Electronics Chat' started by bundick, Aug 26, 2009.

  1. bundick

    Thread Starter Active Member

    Dec 19, 2007
    It's an old Evinrude Drop down trolling motor. I think its a 25 Lb.
    Inside the motor housing, was this Transistor looking thing.
    It looks just like a TO-55 Package but the numbers are not familiar.
    511855 and then under that was 7922. What is this? Anybody know?:)

    evinrude transistor 003.jpg

    Senior Member

    May 26, 2009
    This definitely looks like a transistor. It might be obsolete now, how old is the equipment that the transistor is in? Also, did you try a google search on both of the numbers? Does it have three pins?
    Last edited: Aug 26, 2009
  3. Ron H

    AAC Fanatic!

    Apr 14, 2005
    Could be a thermal cutoff switch.
  4. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    A 7924 is a -24v regulator, but the 7922/LM7922 doesn't exist. No luck searching 511855 either.

    Please show the back of the part, and more details where it was connected etc.

    How old is this thing?? I didn't even recognise the makers logo but did manage to find it;
    Lansdale Semiconductor;

    I tried Lansdale's new web site, no search found for 7922 or 511855.
  5. bertus


    Apr 5, 2008

    The 7922 is probably the production date : week 22 of 1979.
    The 511855 could not be found.

  6. danny.alphaone

    New Member

    Aug 22, 2009
    The device is indeed made in the 22nd week of '79...
    The number is almost certainly an in-house number...
    Very commonly used from the 50s to the 80s...
    Not so much need now with PALs and ROMs, It was all about IP protection.
    The device can be identified by providing its function, if it is a transistor in an inductive circuit, ie a sparking coil, if it has a reverse connected diode across it the Vce will probably be around 100volts, while the continuous current rating would be maybe 15amps. That would make it something like a 2n3055 which is NPN and very common.
    By the way this is my 1st post anywhere... I hope it fits ok.
    Greetings from Danny McBride of Auckland New Zealand.
  7. bundick

    Thread Starter Active Member

    Dec 19, 2007
    I did try the google search. It was confusing because somebody does make a power transistor called a 7922.
    Here's the back. It has an aluminum plate, like a heat sinc, and a resistro across the terminals and a small bolt though the heat sync that is the mounting bolt for the device. I think the bolt made contact with the endcap of the motor for the ground or static ground pin. The resistor is Brown/black/black/silver. Yes, I've just plain forgotten a lot of that stuff. 10 Ohm, 20%?:rolleyes:
    evinrude transistor 008.jpg

    evinrude transistor 010.jpg
  8. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    What connected to the third terminal? It just has the insulator showing, the wire may have corroded away.
  9. bundick

    Thread Starter Active Member

    Dec 19, 2007
    RB you may be right. Under that Soft plastic, is a piece of stainless, round, that looks like it might have had a wire coming out of it. The rest of the wiring is gone though. I guess we'll never know.
    Thanks for the help anyway.;)
  10. Perfectboy

    New Member

    Sep 9, 2009
    I still think it's a transistor, although it is very old. The structure of it tells us.