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Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1)

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On 2017-02-10 16:50, Dave M wrote:
> Dave M wrote:
>> On Fri, 10 Feb 2017 14:55:27 -0800, Joerg <news@analogconsultants.com>
>> wrote:
>>
>>> On 2017-02-10 09:50, Phil Hobbs wrote:
>>>> On 02/10/2017 04:26 PM, Joerg wrote:
>>>>> On 2017-02-10 12:32, Piglet wrote:
>>>>>> On 10/02/2017 17:10, Joerg wrote:
>>>>>>> On 2017-02-10 08:39, bitrex wrote:
>>>>>>>> What are D1-D5?
>>>>>>>>
>>>>>>>> http://www.seekic.com/uploadfile/ic-circuit/s2009713233931554.gif
>>>>>>>
>>>>>>>
>>>>>>> Could they be Shockley diodes? Those are similar to SCRs but
>>>>>>> without a gate connection and can only be triggered via
>>>>>>> avalanche breakdown or dv/dt.
>>>>>>>
>>>>>>
>>>>>> Yeah could be Shockley diodes (aka 4-layer diodes) but last time
>>>>>> I saw one in a schematic the symbol was different. However they
>>>>>> are not hi-speed parts and even in their heyday would not have
>>>>>> seen use at 00s of kilohertz let alone megahertz.
>>>>>>
>>>>>
>>>>> Schematic symbols in the olden days were often weird. Take a look
>>>>> at the potmeter representations here (9th and 10th left from the
>>>>> top):
>>>>>
>>>>> http://www.radiomuseum.org/forumdata/users/133/Symbols_2_590.png
>>>>>
>>>>>
>>>>>> Diac is a still-available kindof breakover diode but higher
>>>>>> voltage and bidirectional. 4-layer diodes I saw were made with
>>>>>> breakover voltages from 8 to 22V and 5-10% tolerance. TC was
>>>>>> remarkable good and they made good semi-precise timers (but not
>>>>>> for nano-seconds). Diacs typically breakover 28-35V and are not
>>>>>> tightly specified.
>>>>>>
>>>>>> Another option is that is just an old symbol for a zener diode?
>>>>>>
>>>>>> But for those speeds I reckon they must be tunnel diodes. That
>>>>>> would tie in with the emitter coupled logic and 10mA tail
>>>>>> current. Tunnel diodes are fast. Due to the very high doping some
>>>>>> older ones have now diffused themselves into mush.
>>>>>>
>>>>>
>>>>> That IC could be from an era where a few hundred kHz was considered
>>>>> blazingly fast. Shockley diodes would offer the nice advantage of
>>>>> introducing hysteresis which improves the noise robustness of this
>>>>> counter.
>>>>>
>>>>> With tunnel diodes I wouldn't know who they'd integrate those onto
>>>>> a chip.
>>>>>
>>>>
>>>> Well, it does say "500MC biquinary counter". ;)
>>>>
>>>> I suspect it was never an actual IC.
>>>>
>>>
>>> With 2k resistors and stuff in there it would never even get into the
>>> VHF range :-)
>>
>>
>> Here's a copy of the circuit as it appeared in Electronics magazine
>> back in 1966.  The diodes are 1N752A Zeners.   It's redrawn here so
>> it's easier to understand.  Just a divide-by-5 ring counter.  Looks
>> like the Zeners are there to protect the B-E junctions of the
>> right-hand transistor of each stage.
>>


Thanks, they are indeed zeners and it is indeed a 500MHz circuit. I'd 
never thought that.


>> Cheers,
>> Dave M
>
> OK... I thought this NG could accept small attachments... Guess not.
> See the image at http://www.ge.tt/2BYDBli2
>

Sometimes it does but most news servers clip that away. Most also won't 
let people subscribe to binary groups so a.b.s.e. has outlived its 
usefulness.

-- 
Regards, Joerg

http://www.analogconsultants.com/

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An old "500MC biquinary counter" bitrex <bitrex@de.lete.earthlink.net> - 2017-02-10 11:39 -0500
  Re: An old "500MC biquinary counter" Joerg <news@analogconsultants.com> - 2017-02-10 09:10 -0800
    Re: An old "500MC biquinary counter" "tom" <tmiller11147@verizon.net> - 2017-02-10 13:24 -0500
      Re: An old "500MC biquinary counter" John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-10 11:30 -0800
        Re: An old "500MC biquinary counter" pcdhobbs@gmail.com - 2017-02-10 12:36 -0800
          Re: An old "500MC biquinary counter" John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-10 14:15 -0800
            Re: An old "500MC biquinary counter" Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-10 13:16 -0500
              Re: An old "500MC biquinary counter" John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-10 16:14 -0800
                Re: An old "500MC biquinary counter" Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-10 19:19 -0500
    Re: An old "500MC biquinary counter" pcdhobbs@gmail.com - 2017-02-10 10:23 -0800
      Re: An old "500MC biquinary counter" Joerg <news@analogconsultants.com> - 2017-02-10 11:16 -0800
        Re: An old "500MC biquinary counter" John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-02-10 11:27 -0800
        Re: An old "500MC biquinary counter" pcdhobbs@gmail.com - 2017-02-10 12:32 -0800
          Re: An old "500MC biquinary counter" bill.sloman@ieee.org - 2017-02-10 16:05 -0800
          Re: An old "500MC biquinary counter" "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-11 10:28 -0600
    Re: An old "500MC biquinary counter" Piglet <erichpwagner@hotmail.com> - 2017-02-10 20:32 +0000
      Re: An old "500MC biquinary counter" Joerg <news@analogconsultants.com> - 2017-02-10 13:26 -0800
        Re: An old "500MC biquinary counter" Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-10 12:50 -0500
          Re: An old "500MC biquinary counter" Joerg <news@analogconsultants.com> - 2017-02-10 14:55 -0800
            Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1) Dave M <dgminala at mediacombb dot net> - 2017-02-10 18:41 -0600
              Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1) "Dave M" <dgminala@mediacombb.net> - 2017-02-10 18:50 -0600
                Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1) Joerg <news@analogconsultants.com> - 2017-02-10 16:58 -0800
                Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1) Clifford Heath <no.spam@please.net> - 2017-02-11 14:29 +1100
                Re: An old "500MC biquinary counter" - 500 MC Bi-Quinary Counter.gif (0/1) whit3rd <whit3rd@gmail.com> - 2017-02-11 02:48 -0800
            Re: An old "500MC biquinary counter" Piglet <erichpwagner@hotmail.com> - 2017-02-11 11:00 +0000
          Re: An old "500MC biquinary counter" "Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com> - 2017-02-11 20:57 -0500
            Re: An old "500MC biquinary counter" krw@notreal.com - 2017-02-11 22:07 -0500
            Re: An old "500MC biquinary counter" Clifford Heath <no.spam@please.net> - 2017-02-12 18:21 +1100
              Re: An old "500MC biquinary counter" krw@notreal.com - 2017-02-12 17:04 -0500
      Re: An old "500MC biquinary counter" Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-10 14:40 -0700
        Re: An old "500MC biquinary counter" bitrex <bitrex@de.lete.earthlink.net> - 2017-02-10 17:59 -0500
        Re: An old "500MC biquinary counter" bitrex <bitrex@de.lete.earthlink.net> - 2017-02-10 18:04 -0500
          Re: An old "500MC biquinary counter" dagmargoodboat@yahoo.com - 2017-02-11 06:41 -0800
  Re: An old "500MC biquinary counter" rickman <gnuarm@gmail.com> - 2017-02-11 07:10 -0500
    Re: An old "500MC biquinary counter" bitrex <bitrex@de.lete.earthlink.net> - 2017-02-11 11:36 -0500

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