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Online parts stores? Where do you buy your stuff?

Discussion in 'Electronic Basics' started by [email protected], Jun 23, 2007.

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  1. Guest

    hi,
    I've been looking around for a good online store to chop for things
    like Transistors, Diodes, Resistors ... etc
    Does anyone know of a good/reliable online store for things like
    that?

    It has to have a location in the US.

    Thanks
    RK
     
  2. http://www.digikey.com/
    www.mouser.com

    Both will send you huge, detailed catalogs if you ask or
    place an order, that are often handy to look through to find
    something before you are sure of the key words for a search.
     
  3. Ulysses

    Ulysses Guest

    There's also bgmicro.com/ allectronics.com, and skycraftsurplus.com.

    Anyone know if anyone still sells bags of misc. switches, diodes, etc like
    they used to?
     
  4. I'm also curious about bags (1000-lot) of general purpose transistors,
    as well. I used to find them at about $10 each (1 cent/BJT) quite
    often, but not so much anymore. (I give these away to students, which
    is why the desire for cheap and general purpose and 1000's.)

    Jon
     
  5. Guest

    I look for that sort of thing on eBay, these days.

    e.g.
    http://cgi.ebay.com/DTC143ES-TP-NPN-Transistor-1000pc-Lot_W0QQitemZ150135316453
    http://cgi.ebay.com/DTC124ES-TP-NPN-Transistor-1000pc-Lot_W0QQitemZ150135317992
    http://cgi.ebay.com/2N3904-General-Purpose-NPN-Transistors-300-Pieces-lot_W0QQitemZ140131874406
    http://cgi.ebay.com/Lot-Of-1000-Zener-Diodes-5-6V-5-6-Volts-500mW-DO-35_W0QQitemZ120133300040
    http://cgi.ebay.com/1-Lot-of-1000-Rectifier-Diodes-1N4001-New-parts_W0QQitemZ320128828674
    http://cgi.ebay.com/HUGE-LOT-ASSORTED-LEDs-LED-LIGHT-EMITTING-DIODE-3mm-5mm_W0QQitemZ200121803262

    But check against the quantity price at Digikley and Mouser before
    bidding.
     
  6. I've spent time on ebay regarding this very issue. I rarely find the
    kind of deals I'm looking for, plus the risk is higher than buying
    from the surplus places who used to carry these bags as a more regular
    matter. For example, the 2N3904 link you provided is a minimum of $12
    for 300 pieces. That's 4 cents each. A 'buy it now' is $14. Higher
    still. Plus, I'm at risk on ebay. I've had troubles in buying from
    unscrupulous folks there with 'high ratings' and I don't relish the
    idea of risking more of the same. Not at those prices. Anyway, at
    that rate, you are right that I should consider places like digikey
    and mouser. Peace of mind and reasonable pricing, sometimes.

    The other two are starting at $17/1000, which isn't too bad but still
    almost twice what I paid a few years back. And that's only assuming I
    can get them at the starting bid. I'll consider the idea. Wish it
    were cheaper, though.

    By the way... why is it that the TO-18's R(theta_JC) is no better than
    for those little plastic TO-92's?

    Jon
     
  7. Jonathan Kirwan wrote:
    (snip)
    The metal surface the die is mounted on is not the one that
    gives off the heat, but is welded to it. The heat goes out
    in all directions through the epoxy in a TO-92.

    By the way, there are some high power sort-of TO-92
    transistors made with heavy copper lead frames, where you
    heat sink through the collector lead (real short and
    soldered to a large copper area). Zetex makes these.
    e.g.:
    http://www.zetex.com/3.0/pdf/ZTX851.pdf
    They also have one flat side and one mostly flat side, so
    they can be better clamped between two flat heat sink
    surfaces with only a thin layer of epoxy on each side.
     
  8. Tom Horsley

    Tom Horsley Guest

    Or even if you ask them not to send you the catalogs. I bought $5
    worth of parts from Mouser once, and they've spent 10 times that
    on postage since then :).
     
  9. Guest


    Funny you mention that... I bought a $38 car part from a guy (with
    high positive feedback) on eBay; it arrived broken. Seller was a
    jerk; it took a Dispute with PayPal to get my money back. (Took 30
    days, but it was finally settled.)

    Don't be shy of filing a dispute with PayPal if you have a bad seller.

    Michael
     
  10. Been there, done that. Still, life is just too short for it. I avoid
    ebay most of the time. (It has to be a very, very serious enticement
    to get my attention.)

    Jon
     
  11. I had earlier imagined that such must be the case. I also opened
    them, so I know first hand what it looks like in there and agree with
    your point for those I've opened. Is this the same case, though, for
    those in TO-18, where there are only two leads coming out and the case
    is the collector? Did they do that in those cases __because__ they
    were doing something more like what I see in TO-3 cans, where heat
    removal is more important?

    And I see what you mean about the heat sinking in that Zetex part.
    Those things are EXPENSIVE, though. 77 cents in 100's and almost 50
    cents in 1000's. And the Rth is still at 150 K/W to ambient (which
    isn't too different from what I'd expect as the package surface area
    and plastic material is the same.) I seem to have remembered about
    that figure for TO-92s, generally. The 50 K/W to case seems just a
    little lower, so that's nice. Not excessively so, enough to make it
    worth that much to me.

    Thanks,
    Jon
     
  12. Ulysses

    Ulysses Guest

    I've bought a lot of stuff from eBay and had very few problems. I never bid
    on anyone who has less that a 98.6 approval rating. If they have a high
    score (such as in the thousands) and a high approval rating they must not be
    too bad.


    Not at those prices. Anyway, at
    Places like All Electronics used to sell a bag of resistors, switches etc
    for about a dollar. I guess they decided they can make more money by
    cataloging each individual piece. I have several things that need new
    switches and I'm not that particular as to what it looks like. In any case
    I've ordered a lot of stuff from All Electronics and never had any problems.
     
  13. Ulysses

    Ulysses Guest

    I bought a "New In Box" DVD recorder on eBay and it turned out to be
    "factory refurbished" which means it probably had something wrong with it so
    it was returned. I did the PayPal dispute thing and it would have ended up
    costing me several dollars to end up with nothing, so I kept it. It died
    shortly after the brief warranty expired. PayPal, however, didn't give me
    any crap.
     
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