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Obsolete Dual Diode Specs

Discussion in 'Power Electronics' started by Rustknot, Oct 24, 2019.

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  1. Rustknot


    Oct 24, 2019
    As I was pawing through my parts bins I came across a few of these International Rectifier DD04-H1 dual diodes and I thought I'd Google the part number and see what the specs were, just because. Nothing, not even something with a close part number or a PDF or scan of an obsolete data book (wish I'd kept more of those) . So does anyone have the data on these?[​IMG]
  2. hevans1944

    hevans1944 Hop - AC8NS

    Jun 21, 2012
    I also spent about an hour searching the web for these with nary a result. Is all you have are "a few of these" and zero prospects of replacing them with a more modern equivalent? If so, I would cut the leads off flush with the case and then crush the epoxy package in a large bench vice before throwing the parts away, just to avoid the temptation of "designing" this component into a project that cannot be maintained with commercial off-the-shelf parts.

    OR... if you are a hobbyist and enjoy resurrecting ancient semiconductors for one-off projects for personal enlightenment and joy... buy or build a transistor tester that will measure the specifications you need to know that are applicable to these two diodes.

    FIrst, determine whether you have a plain old silicon device (likely), instead of the more rare germanium rectifier pair or
    Schottky rectifier pair, by measuring the forward current as a function of forward voltage. Do this also for a common 1N4004 silicon diode for comparison. If you have a Schottky diode handy, measure that for comparison. Plot the results on graph paper so you can easily compare the characteristic curves. Try to keep the power low, say less than a watt, when performing this forward voltage test to avoid cooking the semiconductor junctions. Perform this measurement quickly, again to avoid overheating the junction, since the epoxy case will allow heat to escape very slowly. Try to keep the duty cycle below five or ten percent. Later, you can measure the case temperature rise above ambient at a particular operating forward current and try to use this information along with the thermal properties of typical epoxies to infer what the junction temperature of the diode is. Try to stay below 100C for longer life.

    Second, measure the reverse leakage current as a function of reverse bias voltage applied to each diode. Make sure the measurement is current-limited to, say, 10 microamperes so the diode doesn't self-destruct under avalanche breakdown conduction while making the measurement. If breakdown voltage occurs with less than about 100 volts reverse bias, you may have a zener diode. Zener diodes with established specifications are readily available and inexpensive, so unless you have two that are closely matched, cut the leads off and smash the case of that puppy to avoid future frustration. You should probably do this even if the diodes ARE closely matched since the chances of every obtaining spares are slim to none.

    Assuming the diode pair has acceptable forward current capability and acceptable reverse leakage capability, congratulations! You now have an irreplaceable substitute for, say, a pair of 1N4002 rectifier diodes. Build it into a custom circuit and let it be someone else's problem further down the road if it fails. Leave no clues behind that modern substitutions are available! Fully half the "fun" of troubleshooting and repair of ancient electronics is finding "stuff" that will work while satisfying the owner that you repaired his heirloom-quality, veneered mahogany, Wavemaster ALL-BAND Shortwave Radio to better than factory new condition. However, never let them peek behind the curtain. Dangerous high voltages and radiation are present inside!

    As @73's de Edd would say, THAAAS it! With good forward voltage at a reasonable current with sufficient reverse voltage capability, you have salvaged a nice pair of power rectifier diodes. Go play and sin no more.

    There are a lot more tests you could do to firmly establish what it is you have on hand, and with that data you could do a parametric search of currently available parts to find suitable replacements, but why bother? Establish the specs for your circuit first, then find the components that meet those specs, then hope you complete your project before the components you have selected become no longer available. Been there, done that, but it's becoming increasingly more difficult to keep up.
  3. Rustknot


    Oct 24, 2019
    When posting an fairly esoteric question about a highly replaceable part (that I probably bought as a close-out when I was a 13 year old kid at a Lafayette store 45 or so years ago ) on an internet forum, I kind of thought others might not share in my curiosity so much but I'd give it a stab. I guess curiosity did kill the cat after all.
  4. 73's de Edd

    73's de Edd

    Aug 21, 2015
    Sir " Rusty Knot " . . . . . .

    Nope . . . . you both no win-ee flee chickee dinnah ! . . . . 'tis neither silicon nor germanium . . . . but their exotic forerunner, being of the composition of selenium.

    You just needed to make due reference to your handy-dandy . . . . Beer-stained A- pull- bee caterlog . . .circa 50-60's.

    If you serviced your own tube type Tee-Wee of the 50's and 60's, you may have needed one of those, if the old picture started doing the slippee- slidee to the side.

    Characteristics . . . .

    It has some back resistance, like a germanium diode but the units forward reistance / voltage drop . . . . is atrocious, as being compared to a germanium diode .
    Give it about the same current carrying capability as you would a germanium 1N34 or 1N60.



    Thaaaaaaaaassssssssit . . . . . . . . ( typically meaning, that's about all I have to say for now)

    73's de Edd . . . . .

    Treat each day as your last . . . . . then . . . . . one day . . . . . you're gonna be right !

    hevans1944, Rustknot and Harald Kapp like this.
  5. hevans1944

    hevans1944 Hop - AC8NS

    Jun 21, 2012
    I shared in your curiosity, but I just was not as fortunate as @73's de Edd, who has been there, done that, and probably ate the cat too.

    OMG! How could I have forgotten selenium rectifiers!? Grandfather had stacks of these with vertical convection air-cooling fins, mounted on the wall of his detached single-car garage with packed-earth floor. The floor made a ticklish, high-resistance "ground return" for grandchildren brave enough (or foolish enough) to investigate bare-footed how a full-wave line-operated "battery charger" for Grandfather's '50-something Buick worked. Nary a current limiting resistance in sight (unless a small coil of nichrome wound on a ceramic core served that purpose), but this line-connected contraption kept the six-volt lead-acid battery in the Buick fully float-charged and ready to go any time, any season. You just had to be veeery careful connecting and disconnecting the clip-on leads to the battery posts since gran'pa kept it powered on all the time.

    This being in the 1950s, I hadn't advanced to television repair yet, so I never encountered your dual diodes. In fact, television sets were a new market for consumers then and few people could afford them. My grandparents had one TV in their living room, but it was only used for "special events" like the evening news with Walter Cronkite or popular "game" shows like The $64,000 Question. We didn't find out until much later that some of the game shows had been rigged to select preferred winners. In any case, it was "hands off" between me and their television set.
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