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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 00:40:32 +1000
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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.

Using a properly terminated delay line to set the output pulse width 
could reduce this uncertainty, but I've never done it.

Ghiggino, K.P., Phillips, D., and Sloman, A.W. "Nanosecond pulse 
stretcher",Journal of Physics E: Scientific Instruments, 12, 686-687 (1979).

just used two 5GHz wide-band transistors (BFT95) and was perfectly 
horrible, but it did what Dave Phillips and Ken Ghiggino had wanted me 
to give them, and Ken Ghiggino wrote it up rather badly, but I was able 
to rework the short paper into a form that was publishable and looks 
nice on Ken's CV.

The fact the laser pulses it was designed to detect arrived at a steady 
20MHz meant that it's worst defect didn't matter.

-- 
Bill Sloman, Sydney