Connect with us

PCB reference designator question / iding a component

Discussion in 'Datasheets, Manuals and Component Identification' started by tt500pilot, Jul 22, 2012.

Scroll to continue with content
  1. tt500pilot

    tt500pilot

    4
    0
    Apr 17, 2009
    I have a motor control board with PIC driving an HC595A that is driving a uln2003 that in turn is controling 7 relays that activate various motors. Attached to each output of the uln2003 is an sms component wired in series with the coil (-) that has a PCB reference designator starting with an "E". Can someone tell me what these components are ? There are no markings on the actual device. The "E" is on the PBC. ie: E49,E50,E51,etc...
     
  2. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    Pictures? Also are you sure it's in series and not parallel to the relay? If it's parallel it's likely a fly back diode, in series might be a resistor, a pictures would certainly help in identification...
     
  3. tt500pilot

    tt500pilot

    4
    0
    Apr 17, 2009
    Definitely wired in series. the pads to the right of the"E"'s are where the uln2003 used to be. The lands to the right goto the coil (-). Continuity between both ends of the component both ways.
     

    Attached Files:

  4. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    They might just be shunts that enable or disable features? You can see another larger shunt in the bottom right corner identified with 000, so the use of other shunts on this design is quiet possible...
     
  5. tt500pilot

    tt500pilot

    4
    0
    Apr 17, 2009
     
  6. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    There is no 'standard' that anyone really follows when it comes to PC board silk screens, but there are some standards that some will follow... If one is to follow the common trend E would indicate a terminal...

    As for why there may be several in series, look at the PC board layout, the might have used them as an additional layer to accomplish the layout without bumping up the actual PC board layer count...

    This is only speculation...

    [​IMG]

    http://s3-blogs.mentor.com/tom-haus...-1-standard-ref-des-for-schematic-symbols.png
     
  7. gorgon

    gorgon

    603
    24
    Jun 6, 2011
    Do you know where the PCB is coming from? Which country, nationality? Could it be a language problem?

    TOK ;)
     
  8. tt500pilot

    tt500pilot

    4
    0
    Apr 17, 2009
    It's a Gecko Spa Controller card and everything on it is in English.. but not sure where it was manufactured. It looks like the PCB designer decided to use these components wherever one might want to test the current flow.. so I think CocaCola's suggestion that these maybe very low value resistors/shunts may have solved the mystery. They measure about 0.3 - 0.4 ohms using my EX520.
     
  9. davenn

    davenn Moderator

    13,721
    1,913
    Sep 5, 2009
    They look just small inductors often seen in such places

    Dave
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-