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"Y1" component designation?

Discussion in 'Electronic Repair' started by DaveC, Aug 16, 2003.

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  1. DaveC

    DaveC Guest

    Printed on this circuit board next to a component is "Y1". It looks like a
    small tantalum cap (yellow, shiny [epoxy?], "radial" leads [side-by-side]).
    Printed on the side of it is a logo (can't make it out) and:

    3.58U

    I don't remember seeing a "Y" designation before. What is it?

    Thanks,
     
  2. Tom Woodrow

    Tom Woodrow Guest

    it is a crystal or ceramic resenator, possibly 3.58mHz

    Tom Woodrow
    www.dacworks.com
     
  3. This makes me wonder: Where did some of these letter designations come
    from? Why are most IC's labeled U1, U2, etc..? I'm guessing Y is from
    crYstal? How about L (or sometimes E) for inductors? Q for transistors?
     
  4. DaveC

    DaveC Guest

    Thanks.

    Is 3.58 MHz common? It looks familiar, like a common TV oscillator frequency,
    IIRC. Should be able to easily find a replacement?
     
  5. It's the color burst reference (at least for NTSC, I don't know about PAL).
    Every TV has one.

    --
    +--------------------------------+----------------------------------+
    | George H. Patrick, III | Resources for PCB Designers on |
    | | the Web - The Designer's Den |
    | | http://www.pcb-designer.com |
    +--------------------------------+----------------------------------+
    | Take what you like and leave the rest... My opinion ONLY. |
    +-------------------------------------------------------------------+
     
  6. Asimov

    Asimov Guest

    "Andrew Rossmann" bravely wrote to "All" (16 Aug 03 07:52:40)
    --- on the topic of "Re: "Y1" component designation?"

    I don't thing the Y prefix is for a crystal. Like was stated I thought
    it was for a resonnant filter, i.e ceramic or other type. These tend to
    have 3 legs instead of a crystal's 2.

    These resonnators are often used to replace a tuned coil because they
    are a lot smaller, have a high Q, and can be more accurate without
    requiring any tuning adjustment.

    AR> From: Andrew Rossmann <[email protected]_junk.comcast.net>
    AR> This makes me wonder: Where did some of these letter designations
    AR> come from? Why are most IC's labeled U1, U2, etc..? I'm guessing Y is
    AR> from crYstal? How about L (or sometimes E) for inductors? Q for
    AR> transistors?
    AR> --
    AR> If there is a no_junk in my address, please REMOVE it before replying!
    AR> All junk mail senders will be prosecuted to the fullest extent of the
    AR> law!!
    AR> http://home.att.net/~andyross

    .... Dunno if we'll get that past the CSA und UL 'owever.
     
  7. DaveC

    DaveC Guest

    Now I (OP) am confused. It's not a crystal. I thought a ceramic resonator has
    only 2 leads, while a filter has more(?)

    But you say (I think you did...) that it is a filter.

    Can you clarify a little?
     
  8. DaveC

    DaveC Guest

    Jameco has a low-profile xtal that is compatible with some Motorola
    microprocessors, or so this page says:

    <http://www.jameco.com/cgi-
    bin/ncommerce3/ExecMacro/jameco/searchResult.d2w/report?sort=BPA&search=137816
    cd>

    Can I replace a ceramic resonator with this xtal? Do I need to add anything
    else to the circuit?

    Thanks,
     
  9. I'm pretty sure I've seen Y1 to denote crystals, but for the life of
    me I can't be certain. Of course! If nowhere else, the ARRL used Y1
    to denote a crystal. Bill Orr's Radio Handbook used the same prefix.

    Now, I'm not sure the circuit board designator would differentiate
    between a crystal and a ceramic resonator. But since I just scrapped
    a bunch of boards last week, I don't have anything handy to check.
    So I think a manufacturer might use X or Y for the crystal, but
    whatever they used, they'd use it for ceramic resonators.

    Now for the issue of "filter". A lot of these oscillators use a pair
    of capacitors from each side of the crystal (or ceramic resonator)
    to ground:

    ------|Y1|---------
    | |
    C1 C2
    |________|
    ground

    Not all oscillators, just the type you often see in digital equipment.

    You'd need them whether Y1 was a crystal or a ceramic resonator.

    Now, since that's the case, and ceramic resonators can include them,
    you can get ceramic resonators with those two capacitors built in.
    I would not call it a filter, but it would have three leads (the middle
    one being ground). If you put one of those in where the capacitors
    were already in place, you might not get good oscillation.

    There are of course little ceramic things with three leads that are
    indeed filters, as in IF filters. You can use those in oscillators,
    I've seen circuits that sort of amount to novelty, but they are not
    the same thing as the ceramic filters with the built in capacitors.

    Now, if I remember your original post, it sure sounds like a ceramic
    resonator. I'd say they are interchangeable with crystals (or vice
    versa), given the issue of those external capacitors. If the
    circuit expects a resonator with the capacitors, the crystal will
    require external capacitors (because they will not be built in).
    Ceramic resonators are cheaper to manufacture than crystals, and
    not as good in performance as crystals. But for many applications,
    the ceramic resonator is fine. Putting a crystal should be fine,
    though the reverse situation might not be suitable (depending on
    the specific application). There might be a few places where
    the design requires the ceramic resonator, because I gather they
    can be varied in frequency by changing load capacitors, more than
    the average crystal. But that would be a specific exception.

    If the thing has two leads only, then the issue of the extra
    capacitors doesn't exist. Pull a crystal of the correct frequency
    out of something, and there you go.

    Michael
     
  10. DaveC

    DaveC Guest

    There are no caps in this oscillator circuit. The resonator has a 33 ohm (or
    22; I can't tell if those are red or orange stripes) resistor connecting each
    of its 2 pins to ground. One end of the resonator also connects directly to a
    pin of the microcontroller. The other end connects via a 1M ohm resistor to
    another pin of the microcontroller.

    Given this circuit, can I replace the resonator with a crystal? Such as:

    <http://www.jameco.com/cgi-
    bin/ncommerce3/ExecMacro/jameco/searchResult.d2w/report?sort=BPA&search=137816
    cd>

    Thanks,
     
  11. DaveC
    That really really really sounds like 33 pF caps to me. Are those "resistors"
    the same color as the other resistors on the PCB?
     
  12. John Larkin

    John Larkin Guest

    There was, probably still is, a MIL spec that defines standard
    reference designators. It's mostly familiar, with some quaint usages,
    such as D for dynamotor, DS for lamp, and CR (crystal rectifier) for
    diode. I think there's an ANSI standard, too. Nowadays, everybody
    seems to make up their own weird designators, like CON for connector,
    TR for transistor, and IC for, well, an IC.

    Anybody got horrible examples?

    John
     
  13. Tom Woodrow

    Tom Woodrow Guest

    ok 3.58 megacycles
     
  14. Actually, since this is about being picky, that too would be incorrect.

    What you must mean to say is "3.58 megacycles per second". Without
    the additional bit, it technically means nothing, because it does not
    specify the period during which all those cycles are counted.

    When Megahertz were introduced, it was defined as including the "per second"
    bit, making it unnecessary to spell it out.

    Michael
     
  15. And then there's K vs. RY for relays... U vs. IC for integrated circuits...

    I could be wrong, but I was led to believe that resonators have two, and
    ceramic filters have three.
     
  16. Asimov

    Asimov Guest

    "Clifton T. Sharp Jr." bravely wrote to "All" (17 Aug 03 10:18:28)
    --- on the topic of "Re: "Y1" component designation?"

    CTSJ> From: "Clifton T. Sharp Jr." <>

    CTSJ> I could be wrong, but I was led to believe that resonators have two,
    CTSJ> and ceramic filters have three.

    Thanks, you are right there, I mixed the 2 a bit, though I think the
    main difference between them is that a ceramic filter simply gets an
    extra pin attached to it. I experimented with this and found a filter
    will work as a resonnator if the middle pin is just left floating.
    However, I don't recall if the design frequency was affected. Does it?

    Asimov
    ******

    .... I worked hard to attach the electrodes to it.
     
  17. DaveC

    DaveC Guest

    DaveC:

    Clifton T. Sharp Jr.:
    No, they're bright green. Are they caps? I presumed because they're the same
    size as a 1/4 watt resistor and they use the resistor color code that they
    are resistors. Is this "duck" not a duck?

    Thanks,
     
  18. I'm with Clifton. It doesn't quite make sense if they are resistors,
    and the very more so if they were really 22 or 33 ohm resistors. That's
    a pretty big load on the crystal. Take an ohmmeter and measure them. Likely
    you won't see a low resistance across them.

    Michael
     
  19. DaveC

    DaveC Guest

    Dave C:

    Sverre Holm:
    ---

    I'm having a tough time finding a ceramic resonator locally. I know I can
    find one on-line and mail-order. But I want to fix this *now*.

    Can I replace a resonator *directly* with a crystal? Any modifications needed
    to the circuit?

    Thanks,
     
  20. Beware the faulty memory, but if I recall right a filter can have more
    than one resonator element. I suspect the caps might have a small effect
    (there's a cap from each resonator lead to the common IIRC) but it
    shouldn't throw things off wildly; if you were going for that much
    precision you'd have used crystals. :)
     
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