1N34A diode

Discussion in 'Homebrew and Kit Projects' started by K9FV, Oct 10, 2008.

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  1. K9FV

    K9FV Ham Member QRZ Page

    Hello all, I desire a 1N34A germanium diode - those little buggers are hard to find locally. I am wishing to build a RF probe and read that is the best diode for this use. The instructions say a 1N458A will work also, but I'm not able to find either of those locally - and my junk..... ahhh, treasure chest does not contain either part. The 1N34A has a forward voltage of 0.3 while the 1N458A is 1 volt - that makes the 1N34A better.... doesn't it?

    Digi-Key has the 1N458A in stock, BUT only in min of 2,000 and I don't need that many. Mouser has both in stock, but the $6 shipping makes it pretty expensive. Radio Shack does not list either diode on the web catalog. Perhaps a substitute for either that RS might have?

    Any other suggestions for local? I can use thru-hole or SMD version.

    73 de Ken H.
  2. K8ERV

    K8ERV QRZ Member QRZ Page

    Sure I can find one, will send in a few days.

    TOM K8ERV Montrose Colo
  3. K9FV

    K9FV Ham Member QRZ Page

    You a good man Tom - my address on QRZ is good.... I'll be HAPPY to send you back money for postage and cost of diode.

    73 de Ken h.
  4. W4HAY

    W4HAY XML Subscriber QRZ Page

  5. K7FE

    K7FE QRZ Lifetime Member #1 Platinum Subscriber Life Member QRZ Page

    You do not need a 1N34 germanium diode for your RF probe.

    The reasons for using a germanium RF diode have been mostly negated since the development and availability of Schottky diodes. The forward voltage drop is only about 0.1 volt higher (or less) for the Schottky and the newer Schottky is much more rugged than the old Germanium types. That means, you will not be as likely to damage the Schottky when used in your probe.

    Many companies make them and they are used as balanced mixers in almost every modern amateur transceiver.

    If you have an application other than a simple RF probe and you wish a lower Vf (forward voltage drop), just bias the diode slightly to obtain Vf's closer to zero.

    Terry, K7FE
  6. K8ERV

    K8ERV QRZ Member QRZ Page

    You know that , I know that, my wife knows that, but sure hard to convince that dog.

    At the moment I can't find the 34, tho have seen it recently. SOP. I found a 56a with similar ratings and construction, will send it if I can't find the 34.

    No charge, many have helped me.

    TOM K8ERV Montrose Colo
  7. KL7AJ

    KL7AJ Premium Subscriber QRZ Page

    Yah....these things used to grow on trees. If you can't find any, you can go the more expensive route and buy a schottkey diode. Or you actually apply a little bias to a sillycone diode to make it...uh...er....biased
  8. KB7BX

    KB7BX Ham Member QRZ Page


    I am holding 3 Ea. in my hand. If you still want thenm I can put them in the mail tomorrow.

  9. K9FV

    K9FV Ham Member QRZ Page

    Thanks for all the postive response - I just hope I can return the favor sometime.

    Jerry, I am good on QRZ.

    THANKS a whole bunch ya'll (yea, I'm from the south)

    73 de Ken H.
  10. KD8DEY

    KD8DEY Ham Member QRZ Page

    Built one of those....

    Built mine on a terminal strip from Radio Shack, Used a cigar tube to mount it in and wired with an old extra set of probe wires :D if you have an old portable radio in the parts bin you will probably find a couple of them in there. or maybe even in an old CB. You can usually Identify it as the piece dicconnected on one end (breaking the AF-AGC) :D
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