On Tue, 12 Jul 2016 13:48:32 -0700 (PDT), dagmargoodboat@yahoo.com wrote:>On Tuesday, July 12, 2016 at 3:14:43 PM UTC-4, rickman wrote: >> On 7/12/2016 3:08 PM, John Larkin wrote: >> > >> > Mo and I were sitting at a table near the window of our neighborhood >> > French restaurant snacking on beer and oysters and cassoulet (I'm >> > eating the leftover cassoulet this instant... it holds up nicely) and >> > we noted that the entire population of the planet could live like >> > this, if people weren't such jerks. >> >> How would that work exactly? How are you going to pay the person who >> collects your garbage or serves you those oysters the same as what you >> make? Sounds very socialistic to me. >> >> -- >> >> Rick C > >Why are we wealthier than the cavemen? We both started with the same >raw materials (and in fact they had them arguably greater abundance, >since none of them had been used). So why? > >The answer lies in our accumulated knowledge, and our codes of conduct, >with the latter a /sine qua non/ for the former. > >But socialistic codes of conduct have a poor history for creating wealth. >Rather, they prey on wealth once it exists, dragging it down. > >"There is in fact a manly and legitimate passion for equality that spurs > all men to wish to be strong and esteemed. This passion tends to elevate > the lesser to the rank of the greater. But one also finds in the human > heart a depraved taste for equality, which impels the weak to want to > bring the strong down to their level, and which reduces men to preferring > equality in servitude to inequality in freedom." > > --Alexis de Tocqueville, Ancien Regime and the Revolution > >Cheers, >James ArthurYou're whetting my appetite... time to re-read de Tocqueville, Mill, Rousseau and Burke. (I wanted to name our first son John Stuart, so we settled on Aaron David ;-) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I'm looking for work... see my website.
Zener diode below-threshold reverse current
Started by ●June 23, 2016
Reply by ●July 12, 20162016-07-12
Reply by ●July 12, 20162016-07-12
On Tue, 12 Jul 2016 13:48:32 -0700 (PDT), dagmargoodboat@yahoo.com wrote:>On Tuesday, July 12, 2016 at 3:14:43 PM UTC-4, rickman wrote: >> On 7/12/2016 3:08 PM, John Larkin wrote: >> > >> > Mo and I were sitting at a table near the window of our neighborhood >> > French restaurant snacking on beer and oysters and cassoulet (I'm >> > eating the leftover cassoulet this instant... it holds up nicely) and >> > we noted that the entire population of the planet could live like >> > this, if people weren't such jerks. >> >> How would that work exactly? How are you going to pay the person who >> collects your garbage or serves you those oysters the same as what you >> make? Sounds very socialistic to me. >> >> -- >> >> Rick C > >Why are we wealthier than the cavemen? We both started with the same >raw materials (and in fact they had them arguably greater abundance, >since none of them had been used). So why? > >The answer lies in our accumulated knowledge, and our codes of conduct, >with the latter a /sine qua non/ for the former. > >But socialistic codes of conduct have a poor history for creating wealth. >Rather, they prey on wealth once it exists, dragging it down. > >"There is in fact a manly and legitimate passion for equality that spurs > all men to wish to be strong and esteemed. This passion tends to elevate > the lesser to the rank of the greater. But one also finds in the human > heart a depraved taste for equality, which impels the weak to want to > bring the strong down to their level, and which reduces men to preferring > equality in servitude to inequality in freedom." > > --Alexis de Tocqueville, Ancien Regime and the Revolution > >Cheers, >James ArthurEven a modern socialist train wreck like Cuba or Venezuela is better than a primitive society whose favorite pastime is tribal warfare. The socialists still have mail service, so can always get by on remittences from the USA. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●July 12, 20162016-07-12
Den tirsdag den 12. juli 2016 kl. 23.56.53 UTC+2 skrev John Larkin:> On Tue, 12 Jul 2016 13:48:32 -0700 (PDT), dagmargoodboat@yahoo.com > wrote: > > >On Tuesday, July 12, 2016 at 3:14:43 PM UTC-4, rickman wrote: > >> On 7/12/2016 3:08 PM, John Larkin wrote: > >> > > >> > Mo and I were sitting at a table near the window of our neighborhood > >> > French restaurant snacking on beer and oysters and cassoulet (I'm > >> > eating the leftover cassoulet this instant... it holds up nicely) and > >> > we noted that the entire population of the planet could live like > >> > this, if people weren't such jerks. > >> > >> How would that work exactly? How are you going to pay the person who > >> collects your garbage or serves you those oysters the same as what you > >> make? Sounds very socialistic to me. > >> > >> -- > >> > >> Rick C > > > >Why are we wealthier than the cavemen? We both started with the same > >raw materials (and in fact they had them arguably greater abundance, > >since none of them had been used). So why? > > > >The answer lies in our accumulated knowledge, and our codes of conduct, > >with the latter a /sine qua non/ for the former. > > > >But socialistic codes of conduct have a poor history for creating wealth. > >Rather, they prey on wealth once it exists, dragging it down. > > > >"There is in fact a manly and legitimate passion for equality that spurs > > all men to wish to be strong and esteemed. This passion tends to elevate > > the lesser to the rank of the greater. But one also finds in the human > > heart a depraved taste for equality, which impels the weak to want to > > bring the strong down to their level, and which reduces men to preferring > > equality in servitude to inequality in freedom." > > > > --Alexis de Tocqueville, Ancien Regime and the Revolution > > > >Cheers, > >James Arthur > > Even a modern socialist train wreck like Cuba or Venezuela is better > than a primitive society whose favorite pastime is tribal warfare. >https://youtu.be/tA3L7RG8bnA
Reply by ●July 12, 20162016-07-12
On Tuesday, July 12, 2016 at 9:09:07 PM UTC+2, John Larkin wrote:> On Tue, 12 Jul 2016 10:51:20 -0700 (PDT), dagmargoodboat@yahoo.com > wrote: > > >On Tuesday, July 12, 2016 at 11:50:24 AM UTC-4, Lasse Langwadt Christensen wrote: > >> Den tirsdag den 12. juli 2016 kl. 17.41.01 UTC+2 skrev rickman: > >> > On 7/12/2016 9:44 AM, Phil Hobbs wrote: > >> > > On 07/10/2016 08:38 PM, M Philbrook wrote: > >> > > > >> > >>> > >> > >> You know what they say John, misery loves company! > >> > > > >> > > As an aside, that's an instance where a sarcastic twist on an old saw > >> > > has taken over from the original meaning, which of course was, > >> > > > >> > > "People who are sad or in trouble feel better if you go visit them." > >> > > >> > I didn't see a smiley so I have to assume you are serious. That's not > >> > what it means. It means we find it hard to be sympathetic when we are > >> > miserable and have little pity for others. Or, seeing others as > >> > miserable as ourselves makes us feel better. > >> > > >> > I heard a report on the radio the other day that essentially said this. > >> > We don't measure our life situation in absolute terms, rather in > >> > relative terms compared to those around us. > >> > >> that explains the popularity of reality shows with dumb people and > >> dysfunctional families > >> > >> -Lasse > > > >I think it accounts for political differences too. > > > >"The French want no-one to be their superior. The English want inferiors. > > The Frenchman constantly raises his eyes above him with anxiety. The > > Englishman lowers his beneath him with satisfaction." > > --Alexis de Tocqueville > > > >But I measure my life in absolute terms, not against what others have. > >If I'm warm, with enough to eat, I'm happy! And when I do measure > >against others, I find tremendous bounty in what others scorn-- > > > > the poorest American can buy strawberries out of season, bananas from > >Honduras, kiwis from God knows where, has a car, an air conditioner, > >a cell phone, and a TV. 100 years ago, no king had any of those. > > > >Too many people worry not that they have enough, but that someone else > >has more. > > > >We truly live like kings. No--better.Kings didn't actually live comfortably. They lived impressively, which isn't necessarily the same thing.> Mo and I were sitting at a table near the window of our neighborhood > French restaurant snacking on beer and oysters and cassoulet (I'm > eating the leftover cassoulet this instant... it holds up nicely) and > we noted that the entire population of the planet could live like > this, if people weren't such jerks.You've not only got enough to eat, but somebody else cooked it for you. Everybody he entire planet could have enough to eat, but it would require a more complicated political re-organisation than is implied by "if people weren't such jerks". Having somebody else cook the food for everybody on the planet would be a little more complicated.> The average person in a developed country does live better than Henry > 8th or Louis 14th. I bet the beer and wine at 7-11 is better than > anything they had.Henry the 8th seems to have die from complications of obesity - like many Americans today. Medical science may manage the complications better today, but it hasn't solved the problem of people eating themselves to death. Louis the 14th lived a very public life - even his getting out bed in the morning was a choreographed ceremony. The wine he drank was probably as good as anything you can buy today - a lot of the wine sold to the palace would have been rubbish, but the royal caterers would have passed off all but the very best to lesser dignitaries. 7-11 doesn't stock the high quality wines that I drink, and it certainly doesn't stock the wines from the vineyards that were famously good back in Henry the 14th's day, and still command premium prices today, if you can find a wine merchant who stocks them. "Living like a king" is one of those sayings that doesn't bear much examination. Kings still get assassinated - though less often than they used to. -- Bill Sloman, Sydney
Reply by ●July 27, 20162016-07-27
On Sun, 10 Jul 2016 17:15:51 -0400, rickman <gnuarm@gmail.com> wrote:>On 7/10/2016 5:01 PM, John Fields wrote: >> On Thu, 23 Jun 2016 22:49:35 -0400, krw <krw@nowhere.com> wrote: >> >>> On Thu, 23 Jun 2016 21:07:54 -0500, Tim Wescott <tim@seemywebsite.com> >>> wrote: >>> >>>> On Thu, 23 Jun 2016 16:20:27 -0700, Jim Thompson wrote: >>>> >>>>> On Thu, 23 Jun 2016 17:42:40 -0500, Tim Wescott >>>>> <seemywebsite@myfooter.really> wrote: >>>>> >>>>>> I know the theory, more or less. >>>>>> >>>>>> In practice, what's the reverse current through a zener diode at levels >>>>>> well below the breakdown voltage? I've got a circuit where I'm feeding >>>>>> a 12V linear regulator with a 25V line. It would be handy to put a >>>>>> zener diode in there so that when the 25V line drops to 4V the current >>>>>> into the regulator drops to tens of microamps. I'm wondering if a >>>>>> series zener will do it. >>>>> >>>>> Clear as mud ;-) Post a schematic of what you mean... 25V -> 4V ?? >>>>> >>>>> ...Jim Thompson >>>> >>>> Sorry. When the circuit is nominally on I want to make 12V from the 25V >>>> rail with a linear regulator. When the circuit is nominally off the 25V >>>> rail is at 4V, and I would like to effectively shut off the 12V line >>>> entirely. >>>> >>>> A 6.8V zener would make for around 18V at the input to the regulator, so >>>> the "on" part works fine. I'm just wondering if, with 4V on one side and >>>> a regulator input on the other, if the zener will flow some predictably >>>> low current. >>> >>> 6.8V zeners suck. I'd just use an enable pin on the regulator.--- Actually, raw 6.8 volt Zeners pretty much rule in terms of voltage tempco, so they don't suck as much as you claim. --->> And if the regulator of choice has no ENABLE pin, then what? > >Then "choise" another regulator... There is no shortage of suitable >regulators in spite of the inability of some people to find them.--- "Choise"??? --->>> Some have an accurate reference so you can program the dropout voltage with >>> just a voltage divider. When the input drops below that value, the >>> regulator shuts off (see: UVLO - Under Voltage Lock Out). >> >> --- >> Wescott was obviously referring to a three terminal series regulator, >> so your rsponse is irrelevant. >> >> As to your damnation of 6.8 volt Zeners, 6.8 volts is pretty close to >> where, with the specified reverse current through the diode, the >> Zener's tempco goes away, so why would you think 6.8 volt Zeners suck? > >If someone wants to limit themselves to unsuitable regulators, then it >can be hard to help them with electronics design. Tim is willing to >consider regulators with an enable, but he can't see to get past the >limitations of the Digikey selection tool. I recommend starting with >the TI tool on their web site. It's easier to find a part on their site >that meets the requirements.Rather than damning one tool and blessing another, wouldn't it be better to teach a man how to fish?
Reply by ●July 27, 20162016-07-27
On Sun, 10 Jul 2016 14:40:27 -0700, John Larkin <jjlarkin@highlandtechnology.com> wrote:>On Sun, 10 Jul 2016 16:01:50 -0500, John Fields ><jfields@austininstruments.com> wrote: > >>On Thu, 23 Jun 2016 22:49:35 -0400, krw <krw@nowhere.com> wrote: >> >>>On Thu, 23 Jun 2016 21:07:54 -0500, Tim Wescott <tim@seemywebsite.com> >>>wrote: >>> >>>>On Thu, 23 Jun 2016 16:20:27 -0700, Jim Thompson wrote: >>>> >>>>> On Thu, 23 Jun 2016 17:42:40 -0500, Tim Wescott >>>>> <seemywebsite@myfooter.really> wrote: >>>>> >>>>>>I know the theory, more or less. >>>>>> >>>>>>In practice, what's the reverse current through a zener diode at levels >>>>>>well below the breakdown voltage? I've got a circuit where I'm feeding >>>>>>a 12V linear regulator with a 25V line. It would be handy to put a >>>>>>zener diode in there so that when the 25V line drops to 4V the current >>>>>>into the regulator drops to tens of microamps. I'm wondering if a >>>>>>series zener will do it. >>>>> >>>>> Clear as mud ;-) Post a schematic of what you mean... 25V -> 4V ?? >>>>> >>>>> ...Jim Thompson >>>> >>>>Sorry. When the circuit is nominally on I want to make 12V from the 25V >>>>rail with a linear regulator. When the circuit is nominally off the 25V >>>>rail is at 4V, and I would like to effectively shut off the 12V line >>>>entirely. >>>> >>>>A 6.8V zener would make for around 18V at the input to the regulator, so >>>>the "on" part works fine. I'm just wondering if, with 4V on one side and >>>>a regulator input on the other, if the zener will flow some predictably >>>>low current. >>> >>>6.8V zeners suck. I'd just use an enable pin on the regulator. >> >>And if the regulator of choice has no ENABLE pin, then what? >> >>>Some have an accurate reference so you can program the dropout voltage with >>>just a voltage divider. When the input drops below that value, the >>>regulator shuts off (see: UVLO - Under Voltage Lock Out). >> >>--- >>Wescott was obviously referring to a three terminal series regulator, >>so your rsponse is irrelevant. >> >>As to your damnation of 6.8 volt Zeners, 6.8 volts is pretty close to >>where, with the specified reverse current through the diode, the >>Zener's tempco goes away, so why would you think 6.8 volt Zeners suck? >> >>John Fields > >Good grief, you only post here to be deliberately obnoxious. What a >sucky way to live.--- Au contraire. Instead of just flapping your gums, as usual, why don't you state what technical quarrels you have with a 6.8 volt Zener diode, properly biased, having close to zero TC? JF
Reply by ●July 27, 20162016-07-27
Den onsdag den 27. juli 2016 kl. 21.29.30 UTC+2 skrev John Fields:> On Sun, 10 Jul 2016 14:40:27 -0700, John Larkin > <jjlarkin@highlandtechnology.com> wrote: > > >On Sun, 10 Jul 2016 16:01:50 -0500, John Fields > ><jfields@austininstruments.com> wrote: > > > >>On Thu, 23 Jun 2016 22:49:35 -0400, krw <krw@nowhere.com> wrote: > >> > >>>On Thu, 23 Jun 2016 21:07:54 -0500, Tim Wescott <tim@seemywebsite.com> > >>>wrote: > >>> > >>>>On Thu, 23 Jun 2016 16:20:27 -0700, Jim Thompson wrote: > >>>> > >>>>> On Thu, 23 Jun 2016 17:42:40 -0500, Tim Wescott > >>>>> <seemywebsite@myfooter.really> wrote: > >>>>> > >>>>>>I know the theory, more or less. > >>>>>> > >>>>>>In practice, what's the reverse current through a zener diode at levels > >>>>>>well below the breakdown voltage? I've got a circuit where I'm feeding > >>>>>>a 12V linear regulator with a 25V line. It would be handy to put a > >>>>>>zener diode in there so that when the 25V line drops to 4V the current > >>>>>>into the regulator drops to tens of microamps. I'm wondering if a > >>>>>>series zener will do it. > >>>>> > >>>>> Clear as mud ;-) Post a schematic of what you mean... 25V -> 4V ?? > >>>>> > >>>>> ...Jim Thompson > >>>> > >>>>Sorry. When the circuit is nominally on I want to make 12V from the 25V > >>>>rail with a linear regulator. When the circuit is nominally off the 25V > >>>>rail is at 4V, and I would like to effectively shut off the 12V line > >>>>entirely. > >>>> > >>>>A 6.8V zener would make for around 18V at the input to the regulator, so > >>>>the "on" part works fine. I'm just wondering if, with 4V on one side and > >>>>a regulator input on the other, if the zener will flow some predictably > >>>>low current. > >>> > >>>6.8V zeners suck. I'd just use an enable pin on the regulator. > >> > >>And if the regulator of choice has no ENABLE pin, then what? > >> > >>>Some have an accurate reference so you can program the dropout voltage with > >>>just a voltage divider. When the input drops below that value, the > >>>regulator shuts off (see: UVLO - Under Voltage Lock Out). > >> > >>--- > >>Wescott was obviously referring to a three terminal series regulator, > >>so your rsponse is irrelevant. > >> > >>As to your damnation of 6.8 volt Zeners, 6.8 volts is pretty close to > >>where, with the specified reverse current through the diode, the > >>Zener's tempco goes away, so why would you think 6.8 volt Zeners suck? > >> > >>John Fields > > > >Good grief, you only post here to be deliberately obnoxious. What a > >sucky way to live. > > --- > Au contraire. > > Instead of just flapping your gums, as usual, why don't you state what > technical quarrels you have with a 6.8 volt Zener diode, properly > biased, having close to zero TC? >looking at a few datasheets, zero TC is ~5.6V, lowest impedance ~6.8V -Lasse
Reply by ●July 27, 20162016-07-27
On Sun, 10 Jul 2016 17:58:29 -0400, krw@attt.bizz wrote:>On Sun, 10 Jul 2016 16:01:50 -0500, John Fields ><jfields@austininstruments.com> wrote: > >>On Thu, 23 Jun 2016 22:49:35 -0400, krw <krw@nowhere.com> wrote: >> >>>On Thu, 23 Jun 2016 21:07:54 -0500, Tim Wescott <tim@seemywebsite.com> >>>wrote: >>> >>>>On Thu, 23 Jun 2016 16:20:27 -0700, Jim Thompson wrote: >>>> >>>>> On Thu, 23 Jun 2016 17:42:40 -0500, Tim Wescott >>>>> <seemywebsite@myfooter.really> wrote: >>>>> >>>>>>I know the theory, more or less. >>>>>> >>>>>>In practice, what's the reverse current through a zener diode at levels >>>>>>well below the breakdown voltage? I've got a circuit where I'm feeding >>>>>>a 12V linear regulator with a 25V line. It would be handy to put a >>>>>>zener diode in there so that when the 25V line drops to 4V the current >>>>>>into the regulator drops to tens of microamps. I'm wondering if a >>>>>>series zener will do it. >>>>> >>>>> Clear as mud ;-) Post a schematic of what you mean... 25V -> 4V ?? >>>>> >>>>> ...Jim Thompson >>>> >>>>Sorry. When the circuit is nominally on I want to make 12V from the 25V >>>>rail with a linear regulator. When the circuit is nominally off the 25V >>>>rail is at 4V, and I would like to effectively shut off the 12V line >>>>entirely. >>>> >>>>A 6.8V zener would make for around 18V at the input to the regulator, so >>>>the "on" part works fine. I'm just wondering if, with 4V on one side and >>>>a regulator input on the other, if the zener will flow some predictably >>>>low current. >>> >>>6.8V zeners suck. I'd just use an enable pin on the regulator. >> >>And if the regulator of choice has no ENABLE pin, then what? > >Then choose another, asshole.--- That's no help, since hostility leads, reductio ad absurdum, to war. Do you want to declare war with your limited resources? --->When you want to discuss electronics, let us all know.--- I'm always up for that, but your invitation is preumptuous, as if you were running the game. JF
Reply by ●July 27, 20162016-07-27
On Wed, 27 Jul 2016 14:49:40 -0500, John Fields <jfields@austininstruments.com> wrote:>On Sun, 10 Jul 2016 17:58:29 -0400, krw@attt.bizz wrote: >[snip]>> >>Then choose another, asshole. > >--- >That's no help, since hostility leads, reductio ad absurdum, to war. > >Do you want to declare war with your limited resources? >--- > >>When you want to discuss electronics, let us all know. > >--- >I'm always up for that, but your invitation is preumptuous, as if you >were running the game. > >JFkrw stole that line from Larkin... neither are running the game... just seeking attention for their competency-starved egos. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I'm looking for work... see my website.
Reply by ●July 27, 20162016-07-27
On Wed, 27 Jul 2016 14:49:40 -0500, John Fields <jfields@austininstruments.com> wrote:>On Sun, 10 Jul 2016 17:58:29 -0400, krw@attt.bizz wrote: > >>On Sun, 10 Jul 2016 16:01:50 -0500, John Fields >><jfields@austininstruments.com> wrote: >> >>>On Thu, 23 Jun 2016 22:49:35 -0400, krw <krw@nowhere.com> wrote: >>> >>>>On Thu, 23 Jun 2016 21:07:54 -0500, Tim Wescott <tim@seemywebsite.com> >>>>wrote: >>>> >>>>>On Thu, 23 Jun 2016 16:20:27 -0700, Jim Thompson wrote: >>>>> >>>>>> On Thu, 23 Jun 2016 17:42:40 -0500, Tim Wescott >>>>>> <seemywebsite@myfooter.really> wrote: >>>>>> >>>>>>>I know the theory, more or less. >>>>>>> >>>>>>>In practice, what's the reverse current through a zener diode at levels >>>>>>>well below the breakdown voltage? I've got a circuit where I'm feeding >>>>>>>a 12V linear regulator with a 25V line. It would be handy to put a >>>>>>>zener diode in there so that when the 25V line drops to 4V the current >>>>>>>into the regulator drops to tens of microamps. I'm wondering if a >>>>>>>series zener will do it. >>>>>> >>>>>> Clear as mud ;-) Post a schematic of what you mean... 25V -> 4V ?? >>>>>> >>>>>> ...Jim Thompson >>>>> >>>>>Sorry. When the circuit is nominally on I want to make 12V from the 25V >>>>>rail with a linear regulator. When the circuit is nominally off the 25V >>>>>rail is at 4V, and I would like to effectively shut off the 12V line >>>>>entirely. >>>>> >>>>>A 6.8V zener would make for around 18V at the input to the regulator, so >>>>>the "on" part works fine. I'm just wondering if, with 4V on one side and >>>>>a regulator input on the other, if the zener will flow some predictably >>>>>low current. >>>> >>>>6.8V zeners suck. I'd just use an enable pin on the regulator. >>> >>>And if the regulator of choice has no ENABLE pin, then what? >> >>Then choose another, asshole. > >--- >That's no help, since hostility leads, reductio ad absurdum, to war. > >Do you want to declare war with your limited resources? >--- > >>When you want to discuss electronics, let us all know. > >--- >I'm always up for that, but your invitation is preumptuous, as if you >were running the game. > >JFThat's silly. I'm running the game. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
