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When I search for 1N34 on Mouser I get nothing, and when I search for 1N270 diode I only find a note that it is obsolete. What is now used in place of this part?

I am using Ronald Quan's book on building AM radios and he specifies it in several projects. For example, he uses it in his two-transistor reflex radio project. It appears to be in the "detection" part of the circuit.

Tyler Durden
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    Without more information about what you're trying to do, it's hard to recommend a replacement. I'd start with a 1N4004, but maybe you could explain why you're looking for a Germanium diode. – W5VO Apr 06 '14 at 18:54
  • I am using Ronald Quan's book on building AM radios and he specifies it in several projects. For example, he uses it in his two-transistor reflex radio project. It appears to be in the "detection" part of the circuit. – Tyler Durden Apr 06 '14 at 19:05
  • Germanium diodes have a lower forward voltage than silicon, so you'd want to stick to the Germanium. – Passerby Apr 06 '14 at 19:09
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    Could you substitute a Schottky as an AM detector? – markrages Apr 06 '14 at 19:36
  • @TylerDurden Please add your extra details to the body of your question, not as comments. – Adam Lawrence Apr 06 '14 at 20:07

3 Answers3

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Central Semi is still producing the 1N34A. Digi-Key has over 6,000 of them in stock (P/N 1N34A BK-ND), and they're authentic (but not cheap).

The Audio Technician
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  • Welcome to EE.SE. Simple answers that are 2 years late are not likely to get you any upvotes. The way to get upvotes is to provide a good answer to a new question. –  Jul 18 '16 at 21:58
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Hot-carrier or Schottky diodes have largely replaced germanium point-contact diodes such as the 1N34. Typical examples are the 1N5711 or BAT41.

The 1N34A is still widely available.

Leon Heller
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  • "The 1N34A is still widely available." Not from Digi-Key or Mouser, but amazingly, from [Amazon!](http://www.amazon.com/American-Microsemiconductor-P-Q972-1N34A-Germanium/dp/B004XNSJQM) – tcrosley Apr 07 '14 at 00:48
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    We are [told in another thread](http://electronics.stackexchange.com/questions/149484/schottky-diode-as-am-detector) that many "1N34A" on the market today (at least in China) are fakes. So guess I one has to be careful... because the names behind these leftover 1N34As are not major manufacturers. – Fizz Jan 17 '15 at 14:16
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I found that the 1N34A can be had from Scott's Hard to Find Electronic Parts which specializes in items for AM radio construction. The 1N34A is a full upgrade over the 1N34 and completely replaces it.

According to Scott, there is no substitute for the 1N34A due to its uniquely low forward voltage of 0.1 volt. Quoting that site:

Crystal Radio Receivers depend on the 1N34A Germanium Diodes rated Forward Voltage Drop ( The amount of voltage before is starts to conduct ) of .3 volts. Silicon diodes are rated around .7 volts. However the voltage for the 1N34A Diode is measured with a current around 10ma. As the current increases so does the Voltage Drop and vise versa . However the 1N34A Germanium Diode actually starts to conduct at very low voltages. The 1N34A will start to conduct around .1 volt. So in a Crystal Radio Receiver you need only to produce around .1 volt from your Crystal Radio Set to begin to hear a station. That is the reason the 1N34A Diode is so popular with Crystal Radio Set Builders.

Germanium diodes are no longer made in the United States, possibly due to hysterical EPA rules about the use of lead as semiconductor dopants.

Tyler Durden
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    They are not made anymore because there is no market to make them for anymore. – PlasmaHH May 19 '15 at 11:39
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    The EPA hasn't banned anything since DDT, PCBs, asbestos, dioxin and a handful of other substances back in the day. Lead is ok in their book. The European Union on the other hand, has phased out lead in the manufacture of electronics. American companies like to sell electronics to other countries so they have mostly moved to phase it out as well. –  Jan 18 '16 at 03:46
  • As of August 2017 it's Mike's Hard to Find Electronic Parts https://www.mikeselectronicparts.com/product/1n34a/ – user3486184 Sep 02 '17 at 22:42