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Is this the future or what? (MOT)

Discussion in 'Electronic Design' started by Rich Grise, Feb 10, 2004.

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  1. Rich Grise

    Rich Grise Guest

    That's "Marginally on Topic." It's about an electronic thing,
    but not an electronics post. I'm in a state of awe. Where's
    the transporter and holodeck? I just got a HP scanjet 4600.
    (and yes, it's 'a', not 'an', because that's the way HP says
    it in their s/w registration card. apparently you're not
    supposed to say, "an aitch-pee ..." but "a aitch-pee ..." ;-)
    $149.99 at office max. I haven't got it all the way unpacked
    yet - I noticed it uses a special cable with a female wall
    wart jack on a flylead on the USB end. So I pull out the
    wall wart, and it hefts like an empty plastic box - the
    cord is heavier than the power supply, right? So I'm wondering,
    how much power can they get out of this little wimpy thing?
    Why not just pick off USB power? I look. input 100-120 V 60 Hz
    600 mA; 12VDC, 1250mA.

    in a package that, with about 6' of lamp cord, weighs .45 lbs.


    I have a little back-burner project in my box, that's so far
    just a piece of vectorbord, a couple of screws and nuts, two
    filter caps, a fuse, switch, bridge, and Mouser 12VAC 120mA
    transformer, and it and about 4' of lamp cord weighs .40 lbs.

    I.e., approx. 10X the power density.

    I call that Magic. (Any sufficiently advanced technology...)
    But my age approaches the national speed limit. Speaking
    of age, has anybody ever noticed that, upon approaching some
    important milestone, the approach seems asymptotic on some
    level? Well, I ramble. %-}

  2. j.b. miller

    j.b. miller Guest

    I just noticed, being a nickel short of your highway limit, that I have a
    basement FULL of so called odd-ball DIP ICs...4000 series CMOS,dip nc
    relays,8052s,PICs,705Ks,Sibec and other 'development systems' including a
    Domino2 with adc,pressure xducers,maxim parts,natsemi stuff,plus a bag of
    2N6075a left over from homebrewed SSRs. That doesn't include the boxes of
    16BIT ISA cards leftover from 'projects'.
    seems too good to toss,heck I paid good coins for this stuff....but the
    eyesight is failing, and SMT has taken over......

    oh well....
    guess I did right to retire at 45..

    Jay in Greensville,Ontario.
  3. Luck bastard! I'm still struggling at 56! Shoulda stayed with Big Brother
    instead of going on my own. BTW, why Greensville? Nothing out there except
    Webster's Falls and a view off the Escarpment. Or are you a Greensville
    Public / Dundas District alama mater and just can't leave the old place?


    Gerry (originally from around the corner, now in God's Country (Sandbanks
  4. Garrett Mace

    Garrett Mace Guest

    Penn and Teller are now about to reveal what is inside the mysterious box.
    After giving up on the *inverse* Torx head screws recessed into plastic with
    no way to get pliers on them, and probably reverse-threaded, I used a saw.
    This is a photo of the inside of a feather-light 6V 2000ma power supply for
    a digital camera that has since passed on, and was about seven years old:

    Not at all surprising to us young whippersnappers, it's a switcher. These
    days the switchers take up a lot less room too, with special-purpose ICs.
    This power supply is probably twenty times more complex than your typical
    transformer+rectifier+capacitor circuit, but the benefit (at least weight
    vs. power-wise) is clear over heavy magnetics.

    Yes, we got some neat toys to play with these days...but not quite as many
    of us are making any money doing it. I'd never give up electronics, but
    these two years out of school have nearly convinced me I will always need to
    pay for it with some other job.
  5. Haven't you moticed this trend before, Rich? After all, if you tried to
    get 350 watts of power out of a linear power supply, the transformer
    would weigh as much as your head! But that little power supply inside
    your PeeCee is not much heavier than an empty metal box the same size.

    Same thing goes for those 12V to 120V inverters.
  6. gothika

    gothika Guest

    Hey man, it's the same for most of us.
    I've got a fine arts degree in cinematography as well as still
    photography and a BS in photo science.(RIT yet.)
    And over the many years have had to do many other things to pay the
    bills. From Carpentry to landscaping and in between.
    It's and old saw and getting more common every day.
    While I was in LA back in the 80's trying desperately to break in to
    the film industry I worked with a finish carpenter who was a graduate
    of Psychiatry from Harvard medical school yet.
    After establishing a successful practice in LA and working it for 2
    years it was costing as much as he made to keep it going.
    chucked it all in, got a pickup and some tools and took up the trade
    of his father. He's work 6-8 months out of the year doing repair and
    custom cabinet work and take a vacation in the winter and go to the
    carribean. He averaged 100 grand a year and was a whole lot happier.
    (Come to think of it I made more working for him than I ever did
    managing photo labs or running a cine camera.)
    Thank god I'm mostly retired now and just work on projects I want too.
  7. ptaylor

    ptaylor Guest

    A few years ago,my G/f got a flatbed scanner for her PC,and the "wall
    wart" was *extremely* light.I'm figuring there was nothing in there but
    a cap,or power resistor to limit the current,and a rectifier diode,maybe
    a zener diode,or something to chop it down to about 12Vdc.
    The "empty" box ran fairly warm..
    I don't think even a tiny SMPS would have fit in there,and been that
    light..I honestly think there was just a dropping resistor and a
    rectifier in that box!

    perhaps I'll see if I can dig it up,and take it apart,since the scanner
    has been sittin unused on the garage shelf for about 2 years now.
  8. Wanna bet? $10 says it's a SMPS.
    The latest generation of cheap wall-warts (3W or so) are almost the
    size of a mains plug. They are still more expensive than linear ones,
    but maybe not when you add $5-10/kg on for air shipment.

    Best regards,
    Spehro Pefhany
  9. Tim Auton

    Tim Auton Guest

    The SMPS for my Siemens mobile phone, albeit a feeble 5V 400mA output,
    is noticeably smaller and lighter than a normal 3-pin UK mains plug. I
    guess the contents must be perhaps 1 1/4" x 2" x 1/3".

  10. legg

    legg Guest

    No sign of how the power cord entered the box. Is this a wall-wart
    with blade connections integrated into the common-mode choke
    terminals, and exiting on the reverse?

  11. Garrett Mace

    Garrett Mace Guest

    That's a pretty safe bet, as seen in the photo I posted above (but this guy
    seems to not pay attention to things like that, so this might be your chance
    to make a little money, Speff).
  12. It's still a gamble, It's just a guess. ;-) Of course if he's more
    clever than ethical he'll open it up first and then decide whether to
    "bet" or not.

    Best regards,
    Spehro Pefhany
  13. Re: Rich's comment: Maybe it's like "An historical.." versus "A

    I once saw some schematic or layout of a chip that worked rather
    differently. It took 120VAC, rectified and filtered it, and then
    chopped it into some HF that would go thru a small value high voltage
    capacitor without much loss. This small HV cap was the isolation
    between the outside AC and the equipment. Then it was rectified and
    filtered to DC on the equipment side. The usual SMPS uses a magnetic
    field as the isolation between the line side and the equipment side. My
    own personal thought here is that I trust the magnetic field, but I'd
    rather not be near the other method, especially when there's a lightning
    storm nearby.
  14. Yeah, that's the big problem. I saw a batch of 30 wall warts go for two
    dollars on Ebay, but the shipping and handling was something like $30!
  15. Me

    Me Guest

    Not really a new thing. I bought a Scanner 5 years ago, also supplied with
    an Electronic Switching supply as the adapter. It Died (Fried Itself) after
    4 years. Try and replace it, Lots of Fun!

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