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From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: fast discrete PHEMT one-shot
Date: Fri, 17 May 2024 15:43:33 +1000
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On 17/05/2024 12:04 pm, John Larkin wrote:
> On Thu, 16 May 2024 16:41:15 -0400, "Edward Rawde"
> <invalid@invalid.invalid> wrote:
> 
>> "John Larkin" <jjSNIPlarkin@highNONOlandtechnology.com> wrote in message
>> news:9qdc4jdovsm0rousj88ngtn2bj6env9l48@4ax.com...
>>> On Fri, 17 May 2024 00:40:32 +1000, Bill Sloman <bill.sloman@ieee.org>
>>> wrote:
>>>
>>>> On 16/05/2024 11:15 am, John Larkin wrote:
>>>>> On Wed, 15 May 2024 22:46:27 -0000 (UTC), piglet
>>>>> <erichpwagner@hotmail.com> wrote:
>>>>>
>>>>>> John Larkin <jjSNIPlarkin@highNONOlandtechnology.com> wrote:
>>>>>>>
>>>>>>> https://www.dropbox.com/scl/fi/agatzclr8pvr5470g6mc4/Phemt_One_Shot_1.jpg?rlkey=cwnx0qd7ajgnh8otf627x5lku&raw=1
>>>>>>>
>>>>>>> Regular monostables are terribly slow. This one has low prop delay and
>>>>>>> high rep-rate, if the sim is to be believed.
>>>>>>>
>>>>>>> SAV541 is mostly specified as an RF part, but it's a dynamite switch.
>>>>>>>
>>>>>>> I can post a link to the files if anybody wants to play with this. All
>>>>>>> my values are first guesses, no math involved, and it works!
>>>>>>>
>>>>>>> My SAV541 Spice model is a revision of Phil Hobbs' original.
>>>>>>> Mini-Circuits is adamant that they will never provide Spice models, a
>>>>>>> typical RF-bigot attitude.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> Yay! Eccles-Jordan ride again.
>>>>>
>>>>> 1918!
>>>>>
>>>>> I think that was a bistable. I don't know when the monostable was >
>>>>> invented.
>>>>
>>>> https://en.wikipedia.org/wiki/Multivibrator
>>>>
>>>> has a two quotes from 1942 one from 1943 and two from 1949 which make it
>>>> clear that monostable had been invented by then. It sees it as a cut
>>>> down bistable, so Eccles-Jordan is probably a good name.
>>>>
>>>> Since the first multivibrator circuit, the astable multivibrator
>>>> oscillator, was invented by Henri Abraham and Eugene Bloch during World
>>>> War I, it probably isn't the right name.
>>>>
>>>> https://apps.dtic.mil/sti/tr/pdf/AD0410225.pdf
>>>>
>>>> is a 1963 Ph.D. on the bistable circuit.
>>>>
>>>>> People tend to roll eyes when I use one-shots in logic designs. I
>>>>> can't see why.
>>>>
>>>> You can't trigger a one-shot immediately after it has been triggered,
>>>> and the pulse width you get can be reduced if you re-trigger it too soon
>>>> after it has generated it's pulse, when it hasn't entirely recovered.
>>>
>>> The SN74123 retriggerable one-shot, and a Fairchild equivalent, are
>>> over 50 years old.
>>>
>>> And "it's" is not the possessive form. It's means "it is."
>>
>> But it can also mean "it has" and who cares anyway.
>> I often find, when typing fast, that I used the wrong form when I re read my
>> sentence.
>> I even typed dentence then and had to change the d.
> 
> You've got to admit that his pompous lecture, about all the inherent
> defects of one-shots, was amusing.

John Larkin objects to any post that doesn't flatter him. One that 
points out that he didn't do his home work is even more objectionable.

> I tweaked my phemt one-shot a bit, just for fun. I might even have a
> use for it.
> 
> https://www.dropbox.com/scl/fi/zoncsuiz2ifl30i1tw0cl/Phemt_One-shot_2.jpg?rlkey=z77hx5kkdpijmz5rs7ex63jq7&raw=1 
> 
> One cool old circuit that predated ICs was the uni-shot, a single
> transistor and three passives. It was used in model airplane r/c
> transmitters. One of the three passives was a joystick pot.

Eccles-Jordan (more correctly Abraham-Bloch) used valves - they predate 
transistors as well as integrated circuits.

-- 
Bill Sloman, Sydney