Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Bill Sloman Newsgroups: sci.electronics.design Subject: Re: fast discrete PHEMT one-shot Date: Fri, 17 May 2024 15:43:33 +1000 Organization: A noiseless patient Spider Lines: 91 Message-ID: References: <48na4j10neo6bru36kllgm3447dclcrfgg@4ax.com> <9qdc4jdovsm0rousj88ngtn2bj6env9l48@4ax.com> <22ed4jl7ups3c3gjp4mull78gq5aq9rclu@4ax.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Fri, 17 May 2024 07:43:45 +0200 (CEST) Injection-Info: dont-email.me; posting-host="f62cb937bafdd9aad6a022f4fcf8a07f"; logging-data="2152695"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+A1BEij7c7YkSCFn0AJthR8+mLPYHQZ88=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:WZW6An7pXekFrX7ZQvPiawqVDnA= In-Reply-To: <22ed4jl7ups3c3gjp4mull78gq5aq9rclu@4ax.com> Content-Language: en-US Bytes: 4892 On 17/05/2024 12:04 pm, John Larkin wrote: > On Thu, 16 May 2024 16:41:15 -0400, "Edward Rawde" > wrote: > >> "John Larkin" wrote in message >> news:9qdc4jdovsm0rousj88ngtn2bj6env9l48@4ax.com... >>> On Fri, 17 May 2024 00:40:32 +1000, Bill Sloman >>> wrote: >>> >>>> On 16/05/2024 11:15 am, John Larkin wrote: >>>>> On Wed, 15 May 2024 22:46:27 -0000 (UTC), piglet >>>>> wrote: >>>>> >>>>>> John Larkin 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