germanium diode - all gone ?

[ChristianFletcher]

I have been trying to find germanium signal diode at RS but they come up as discontinued. I want to use them in homebrew Watt meters and RF probes. I was looking for a 1N34A. Can anyone suggest and alternative. Should I be looking for something with low junction capacitance or just a low forward voltage.

Confused with regards Chris.

[ppppenguin]

If you can't find a germanium diode you could try a schottky diode. These have a nice low forward voltage but I'm not sure about capacitance.

[mikelect]

Originally Posted by ChristianFletcher

I have been trying to find germanium signal diode at RS but they come up as discontinued. I want to use them in homebrew Watt meters and RF probes. I was looking for a 1N34A. Can anyone suggest and alternative. Should I be looking for something with low junction capacitance or just a low forward voltage.

Confused with regards Chris.

Hi a 1N34A is silicon what you really need is something like an OA91 or OA94 which I think you will find CPC still stock, most Germaniun diodes start with OA HTH

Mike

PS plenty of Germanium diodes here at a good price, nice guy to deal with too

http://www.modecomponents.co.uk/

[ChristianFletcher]

Yes i was going to ask about using Schottky barrier diodes but the look to have a very low Vreverse only 8 volts.

Diode,barrier,Schottky,5082-2835

I cannot believe they dont make germanium diode anymore what about all the home made crystal sets

Chris.

Just Checked RS both OA91 or OA94 are discontinued. (I have and a acounts with RS)

[Skywave]

I have seen many Amateur Radio circuits published for RF-measuring devices over the years that use a 1N914 silicon diode. 1N34 (Germanium) is another favourite - if you can find one!

Al.

[radiogammon]

There are some OA91's currently on eBay at http://cgi.ebay.co.uk/OA91-glass-ger...QQcmdZViewItem

[ronbryan]

Christian

You can still get gold bonded (OA47) and point contact (OA90 or 91) germanium diodes from eBay. If your search string is "germanium diode" you will find quite a few. Mainline Electronics seems to list most of them.

Schottky barrier diodes will have a higher forward voltage drop than Ge. Lower than Si though.


Ron

[Al (astral highway)]

Originally Posted by ChristianFletcher

I have been trying to find germanium signal diode at RS but they come up as discontinued.

Confused with regards Chris.

I have a couple of unused germanium diodes here. I can mail them to you.

Astral

[ChristianFletcher]

Hi Astral

Thanks for the kind offer, But I have quite a few RF projects lined up and knowing my kill rate will need a bucket load.

Thanks Chris

Can you believe that Diodes £1 each

Type Schottky Barrier
Package 15
IF (A) 0.01
Vrrm (V) 8.0
Vf max (V) 0.34
Single/Dual Diode Single

[ChristianFletcher]

Did the ebay £4.50 for 20 off OA91

Still cannot believe RS dont stock em

[jim_beacon]

Farnell have 1N914's in stock.

Jim.

[paulsherwin]

As others have said, there are almost always germanium diodes on eBay, albeit at a price. Any scrap transitor radio will contain at least one

I'm sure they're still being made, if only for use in AM radios, though I suppose the detector is within the all-in-one radio chip these days.

You can also try using the base-collector or base-emitter junction of any germanium transistor you have in the junk box.

Schottkys will work in many germanium applications - scrap switch mode PSUs usually contain several.

Paul

[Ed_Dinning]

Hi Gents, schottkys are available up to about 100V. Capacitance and stored charge are low. They are normally used on SMPS output circuits abd are a good substitute for early Ge power rectifiers. As the thread has shown, plenty of OA types about still.

Ed

[Tim]

Rapid stock them at £0.48p each.

http://www.rapidonline.com/productin...moduleno=73379


1N914=1N4148? Silicon?

[6AL5W-Martin]

germanium diode are not always "OA", the newer first letter for germanium is the "A".

AA113, AA119 are favorites in demodulation. Also saled as selected couples for ratio. Not expensive.

http://www.electronicpool.de/list/index_A_A_AA113_.html
the Company have also Couples in stock

1N914=1N4148? Silicon? true.

[jim_jobe]

J L Birket has CG91s at 20 for £1. (Equiv. OA91)
Jim

[Malcolm G6ANZ]

If any one is still intereted I found some GEX34 and CV448 diodes in the attic. Both are Germanium point contact type. I must have about 50 of each! Let me know and I'll put a couple in an envelope for whoever

Malcolm

[Tom_I]

I have recently bought OA90s and OA91s over the counter at Maplins in Luton - 69p each.

http://www.maplin.co.uk/module.aspx?...9076&doy=22m12

Tom