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Re: Exhausted

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On Fri, 18 Mar 2016 08:35:08 +1000, John Larkin  
<jjlarkin@highlandtechnology.com> wrote:

> On Fri, 18 Mar 2016 07:52:34 +1000, "David Eather" <eather@tpg.com.au>
> wrote:
>
>> On Thu, 17 Mar 2016 01:35:25 +1000, John Larkin
>> <jjlarkin@highlandtechnology.com> wrote:
>>
>>> On Wed, 16 Mar 2016 15:53:04 +1000, "David Eather" <eather@tpg.com.au>
>>> wrote:
>>>
>>>> If any kind soul can help...
>>>>
>>>> There was a short post/note on SED or SEB about a transistor with a  
>>>> 2.5V
>>>> max Vebo and another one with 3.0 max Vebo. I have spent hours looking
>>>> for
>>>> the transistors and have run out of options. Does anyone remember  
>>>> which
>>>> transistor numbers these were?
>>>>
>>>> I'm adding transistor junction breakdown noise to a Arduino and they
>>>> would
>>>> fit the bill perfectly - and cut out problem of providing extra  
>>>> voltage
>>>> sources other than %v power from USB.
>>>>
>>>> As always TIA.
>>>
>>> Just because it's rated for 2.5 volts max doesn't mean it will conduct
>>> at 2.5 or even 5 volts.
>>>
>>> There are other noise sources that don't need a lot of voltge. What do
>>> you want to use the noise for?
>>>
>>>
>>
>> yeah, I've seen that. Phillips (and Motorola) made BC547's break down at
>> 6v but a bunch of Chinese ones I got only started to zener at 9v and  
>> that
>> despite being subjected to intense swearing (9v was the maximum voltage
>> supply that was available and relatively noise free).
>>
>> The desire is to update a design for a cryptographically secure true
>> random number generator. Low voltage zeners are difficult to use as the
>> noise is way down in the mud (the thing has a microcontroller and  
>> crystal
>> in close proximity which is exacerbated if you try to get ride of 1/f
>> noise so you can get random samples fast(ish) - say 50k - 250k sps
>
> Someone mentioned here that transistor b-e junction noise sources
> degrade. That's probably the classic back-bias beta degradation
> mechanism. For some reason, real zener diodes don't do that. Zeners
> can be super stable for thousands of hours.
>
> An 10 volt zener can make several hundred nv/rthz of pretty good
> wideband noise, easily amplified and sliced into a randomish bit
> stream.
>
> https://dl.dropboxusercontent.com/u/53724080/Parts/Zener_Noise.pdf


Thanks for pic.

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Exhausted  "David Eather" <eather@tpg.com.au> - 2016-03-16 15:53 +1000
  Re: Exhausted Klaus Kragelund <klauskvik@hotmail.com> - 2016-03-16 01:07 -0700
  Re: Exhausted George Herold <gherold@teachspin.com> - 2016-03-16 06:04 -0700
    Re: Exhausted "David Eather" <eather@tpg.com.au> - 2016-03-17 00:16 +1000
      Re: Exhausted Allan Herriman <allanherriman@hotmail.com> - 2016-03-16 16:35 +0000
        Re: Exhausted George Herold <gherold@teachspin.com> - 2016-03-16 11:15 -0700
          Re: Exhausted Allan Herriman <allanherriman@hotmail.com> - 2016-03-17 12:11 +0000
      Re: Exhausted mrdarrett@gmail.com - 2016-03-17 10:37 -0700
        Re: Exhausted "David Eather" <eather@tpg.com.au> - 2016-03-18 07:25 +1000
          Re: Exhausted mrdarrett@gmail.com - 2016-03-17 15:05 -0700
    Re: Exhausted Winfield Hill <hill@rowland.harvard.edu> - 2016-03-16 07:32 -0700
      Re: Exhausted George Herold <gherold@teachspin.com> - 2016-03-16 08:04 -0700
        Re: Exhausted Winfield Hill <hill@rowland.harvard.edu> - 2016-03-16 08:16 -0700
        Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-16 10:32 -0700
          Re: Exhausted George Herold <gherold@teachspin.com> - 2016-03-16 11:08 -0700
            Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-16 12:30 -0700
              Re: Exhausted Clifford Heath <no.spam@please.net> - 2016-03-17 06:47 +1100
                Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-16 17:01 -0700
                Re: Exhausted Clifford Heath <no.spam@please.net> - 2016-03-17 07:01 +1100
                Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-16 17:27 -0700
                Re: Exhausted Piotr Wyderski <peter.pan@neverland.mil> - 2016-03-17 17:35 +0100
                Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-17 10:13 -0700
                Re: Exhausted Clifford Heath <no.spam@please.net> - 2016-03-18 11:38 +1100
                Re: Exhausted dplatt@coop.radagast.org (Dave Platt) - 2016-03-16 17:17 -0700
                Re: Exhausted Lasse Langwadt Christensen <langwadt@fonz.dk> - 2016-03-16 17:21 -0700
                Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-16 17:39 -0700
                Re: Exhausted "Tim Williams" <tiwill@seventransistorlabs.com> - 2016-03-16 21:24 -0500
                Re: Exhausted Phil Hobbs <pcdhobbs@gmail.com> - 2016-03-16 20:51 -0700
                Re: Exhausted George Herold <gherold@teachspin.com> - 2016-03-16 20:21 -0700
                Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-16 21:16 -0700
                Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-16 17:34 -0700
                Re: Exhausted "David Eather" <eather@tpg.com.au> - 2016-03-18 07:31 +1000
                Re: Exhausted rickman <gnuarm@gmail.com> - 2016-03-17 00:01 -0400
                Re: Exhausted Clifford Heath <no.spam@please.net> - 2016-03-17 14:09 +1100
                Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-17 09:01 -0700
                Re: Exhausted Piotr Wyderski <peter.pan@neverland.mil> - 2016-03-17 17:46 +0100
                Re: Exhausted "David Eather" <eather@tpg.com.au> - 2016-03-18 07:33 +1000
                Re: Exhausted "David Eather" <eather@tpg.com.au> - 2016-03-18 07:35 +1000
                Re: Exhausted Piotr Wyderski <peter.pan@neverland.mil> - 2016-03-18 11:44 +0100
      low-voltage low-current noise sources Winfield Hill <hill@rowland.harvard.edu> - 2016-03-16 08:10 -0700
  Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-16 08:35 -0700
    Re: Exhausted "David Eather" <eather@tpg.com.au> - 2016-03-18 07:52 +1000
      Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-17 15:35 -0700
        Re: Exhausted "David Eather" <eather@tpg.com.au> - 2016-03-18 09:09 +1000
          Re: Exhausted John Larkin <jjlarkin@highlandtechnology.com> - 2016-03-17 16:54 -0700
          Re: Exhausted George Herold <gherold@teachspin.com> - 2016-03-17 17:40 -0700
            Re: Exhausted mixed nuts <melopsitticus@undulatus.budgie> - 2016-03-17 22:37 -0400
        Re: Exhausted "David Eather" <eather@tpg.com.au> - 2016-03-18 09:09 +1000
        Re: Exhausted George Herold <gherold@teachspin.com> - 2016-03-17 17:29 -0700

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