Author Topic: Identifying fake 1N34s  (Read 1551 times)

Valoosj

Identifying fake 1N34s
« on: May 28, 2013, 11:53:08 AM »
I've just bought a bundle of 1N34s on evilbay and I would like to make sure that I haven't bought fakes.
I read that measuring the forward voltage drop helps, but I couldn't find any specific values to look for.

I measured 20 of them, and about 8 were between 0.2V and 0.3V.
The rest went from 0V to 1V.

Could somebody tell me which value to look for?
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John Lyons

Re: Identifying fake 1N34s
« Reply #1 on: May 28, 2013, 01:07:58 PM »
They are germanium diodes. As long as they have the drop you want then fake or not
it will not matter. .2v - .4v is typical.
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midwayfair

Re: Identifying fake 1N34s
« Reply #2 on: May 28, 2013, 01:11:17 PM »
If you aren't certain that they're germanium, hold your finger on the diode while measuring it and you should see the Fv rise.

0v to 1v -- how are you measuring these? I've never seen a diode below about .17v with my multimeter.
My band, Midway Fair: www.midwayfair.org. Myself's music and things I make: www.jonpattonmusic.com. DIY pedal demos: www.youtube.com/jonspatton. PCBs of my Bearhug Compressor and Cardinal Harmonic Tremolo are available from http://www.1776Effects.com!

Valoosj

Re: Identifying fake 1N34s
« Reply #3 on: May 28, 2013, 01:22:44 PM »
I measured them with my DMM. Maybe they are just broken if they give 0V? None went between 0V and 0.1V ...

"The drop I want" would be a good reference if I knew exactly what it were. 0.25V and 0.8V probably makes a hell of a lot of difference in something like an octavia, no?
What can I use there to define the preferred drop, apart from my ears?
Quote from: frequencycentral
You squeezed it into a 1590A - you insane fool!  :icon_mrgreen:
Quote from: Scruffie
Well this... this is just silly... this can't fit in a 1590B... can it? And you're not even using SMD you mad man!

midwayfair

Re: Identifying fake 1N34s
« Reply #4 on: May 28, 2013, 01:49:22 PM »
I measured them with my DMM. Maybe they are just broken if they give 0V? None went between 0V and 0.1V ...

"The drop I want" would be a good reference if I knew exactly what it were. 0.25V and 0.8V probably makes a hell of a lot of difference in something like an octavia, no?
What can I use there to define the preferred drop, apart from my ears?

The trouble with answering this question is that different multimeters read diodes as different voltage drops. On mine, 1N34A measure between .32v and .4v. Other people report them as consistently measuring lower than .3v. They should be higher than a BAT41 and maybe a little more than half the drop of a 1N914. Unless you use a Peak Atlas, which seems to measure Ge diodes as twice their Fv all the time.

Diodes can be frustrating little buggers.
My band, Midway Fair: www.midwayfair.org. Myself's music and things I make: www.jonpattonmusic.com. DIY pedal demos: www.youtube.com/jonspatton. PCBs of my Bearhug Compressor and Cardinal Harmonic Tremolo are available from http://www.1776Effects.com!