germanium diode oa91 alternative- project

K

kevinkevinx2

New Member

• Dec 21, 2013

• #1

im planning to do this project for school sciance fair: http://www.creative-science.org.uk/mobile_LED.html
I found out the germanium diode oa91 was discontinued and unavailable unless ordered online. due to certain due dates, ordering would be my last option. is there any equivalent or alternate diode that i can use?

 

JimB

Super Moderator

Most Helpful Member

• Dec 22, 2013

• #2

You should be able to find a 1N4148 which will work OK for this circuit.

JimB

 

ronsimpson

Well-Known Member

Most Helpful Member

• Dec 22, 2013

• #3

Looking at the picture there is a small glass diode.
The 1n4148 and 1n914 come in that glass package. If you can't find what you want just try any small glass diode. I started out getting parts out of dead TVs and radios.

 

MikeMl

Well-Known Member

Most Helpful Member

• Dec 22, 2013

• #4

A silicon diode like a 1n914 will have greatly reduced sensitivity as a 1Ghz RF detector compared to a point-contact Germanium diode like the OA91, if it works at all. A small-signal Schottky would be a better choice than a 1n914.

I have dozens of Ge uWave detector diodes around here. Where are you located?

 

audioguru

Well-Known Member

Most Helpful Member

• Dec 22, 2013

• #5

The OA91 was available in Europe. Here in North America we used 1N31A germanium diodes about 60 years ago.

 

4pyros

Well-Known Member

Most Helpful Member

• Dec 22, 2013

• #6

and still available here;
https://www.weisd.com/ProductView.php?PN=1N31A

 

audioguru

Well-Known Member

Most Helpful Member

• Dec 22, 2013

• #7

Look at the high price for that "equivalent" for a cheap old diode.

 

4pyros

Well-Known Member

Most Helpful Member

• Dec 22, 2013

• #8

Ya its a "replacement part"

 

audioguru

Well-Known Member

Most Helpful Member

• Dec 22, 2013

• #9

I don't think that NTE makes anything. They simply buy parts made by other manufacturers, rub off the original part number and put on their own part number then sell it at a much higher price. I forgot to add their "hoarding fee".

 

4pyros

Well-Known Member

Most Helpful Member

• Dec 22, 2013

• #10

If the OP wants to look around some more he may find something more suitable.
The web site said it has to have the wire in it for it to work, there should be more alternatives out there.

 

K

kevinkevinx2

New Member

• Dec 22, 2013

• #11

MikeMl said:

A silicon diode like a 1n914 will have greatly reduced sensitivity as a 1Ghz RF detector compared to a point-contact Germanium diode like the OA91, if it works at all. A small-signal Schottky would be a better choice than a 1n914.

I have dozens of Ge uWave detector diodes around here. Where are you located?

Click to expand...

Hawaii

 

MikeMl

Well-Known Member

Most Helpful Member

• Dec 22, 2013

• #12

kevinkevinx2 said:

Hawaii

Click to expand...

I can throw a couple into a first class envelope. How quick do you need it? Contact me using the forum's Private mail system....