On Thu, 07 Sep 2023 04:58:57 GMT, Jan Panteltje <alien@comet.invalid> wrote:>On a sunny day (Wed, 6 Sep 2023 22:56:12 +0000) it happened chrisq ><devzero@nospam.com> wrote in <udb02d$2m6li$1@dont-email.me>: > >>On 9/6/23 22:34, John Larkin wrote: >>> On Wed, 6 Sep 2023 14:34:12 -0700 (PDT), John Smiht >>> <utube.jocjo@xoxy.net> wrote: >>> >>>> On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote: >>>>> On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com> >>>>> wrote: >>>>>> On 06/09/2023 01:04, John Larkin wrote: >>>>>>> Imagine an NPN transistor. Ground the emitter and connect the >>>>>>> collector to some nice positive voltage. >>>>>>> >>>>>>> Now pull the base negative, through a current-limiting resistor. What >>>>>>> happens? >>>>>>> >>>>>> >>>>>> If the collector is already positive >>>>> That was a stated condition >>>>>> and pullup resistor is not >>>>>> extremely high then I think not much detectable will happen even once >>>>>> the Veb junction breaks down. >>>>> "Detectable" can include amps or picoamps of currents. >>>>> >>>>> Curious that nobody seems to address this case. >>>> >>>> How could the information be used? It seems to have not been needed in the past, yes? >>> >>> I'd expect that understanding transistors is a generally good thing to >>> do. Looking at schematics on the web, it seems like few people do. >>> >>> If it behaves as I suspect it may, I might have a use for it. >>> >> >>Back in the 60's/70's there were some germanium transistors >>marketed for avalanche pulse generator work. May have been >>Mullard / Philips, but don't remember any circuit details. >> >>Years ago, found myself fixing more than a few high power >>audio amps and built a simple breakdown tester with a variac, >>stepdown transformer, limiting resistor and full wave rectifer. >>Got some interesting effects at breakdown, very high frequency >>oscillation on the scope. 2n3055 class power devices, normally >>quite low frequency use. Interesting effect, perhaps similar >>to other weird stuff of the time, like impatt diodes... > >Yes, and not all 2N3055 were the same, different manufactures.. diffferent ft >Build quite a few audio amps with those. > https://en.m.wikipedia.org/wiki/2N3055The old slow klunky RCA 3055's were tough. Fairchild made a "2N3055" that had a tiny chip, was very fast, and tended to blow up.> >Same likely goes for John Larkin's experiment, >And manufacturers can change process any time, not something recommended to use out of spec.That's a problem these days, getti9ng consistent parts, even from one manufacturer. Data sheets don't tell the whole story and in fact try to hide hazards. Sometimes, to get performance, you do what works. We need a web site, icbugs.com or something where people report parts issues.
NPN in unusual quadrant
Started by ●September 5, 2023
Reply by ●September 7, 20232023-09-07
Reply by ●September 7, 20232023-09-07
On Thursday, September 7, 2023 at 11:57:05 AM UTC-5, John Larkin wrote:> On Thu, 07 Sep 2023 04:58:57 GMT, Jan Panteltje <al...@comet.invalid> > wrote: > >On a sunny day (Wed, 6 Sep 2023 22:56:12 +0000) it happened chrisq > ><dev...@nospam.com> wrote in <udb02d$2m6li$1...@dont-email.me>: > > > >>On 9/6/23 22:34, John Larkin wrote: > >>> On Wed, 6 Sep 2023 14:34:12 -0700 (PDT), John Smiht > >>> <utube...@xoxy.net> wrote: > >>> > >>>> On Wednesday, September 6, 2023 at 2:59:10?PM UTC-5, John Larkin wrote: > >>>>> On Wed, 6 Sep 2023 19:19:20 +0100, piglet <erichp...@hotmail.com> > >>>>> wrote: > >>>>>> On 06/09/2023 01:04, John Larkin wrote: > >>>>>>> Imagine an NPN transistor. Ground the emitter and connect the > >>>>>>> collector to some nice positive voltage. > >>>>>>> > >>>>>>> Now pull the base negative, through a current-limiting resistor. What > >>>>>>> happens? > >>>>>>> > >>>>>> > >>>>>> If the collector is already positive > >>>>> That was a stated condition > >>>>>> and pullup resistor is not > >>>>>> extremely high then I think not much detectable will happen even once > >>>>>> the Veb junction breaks down. > >>>>> "Detectable" can include amps or picoamps of currents. > >>>>> > >>>>> Curious that nobody seems to address this case. > >>>> > >>>> How could the information be used? It seems to have not been needed in the past, yes? > >>> > >>> I'd expect that understanding transistors is a generally good thing to > >>> do. Looking at schematics on the web, it seems like few people do. > >>> > >>> If it behaves as I suspect it may, I might have a use for it. > >>> > >> > >>Back in the 60's/70's there were some germanium transistors > >>marketed for avalanche pulse generator work. May have been > >>Mullard / Philips, but don't remember any circuit details. > >> > >>Years ago, found myself fixing more than a few high power > >>audio amps and built a simple breakdown tester with a variac, > >>stepdown transformer, limiting resistor and full wave rectifer. > >>Got some interesting effects at breakdown, very high frequency > >>oscillation on the scope. 2n3055 class power devices, normally > >>quite low frequency use. Interesting effect, perhaps similar > >>to other weird stuff of the time, like impatt diodes... > > > >Yes, and not all 2N3055 were the same, different manufactures.. diffferent ft > >Build quite a few audio amps with those. > > https://en.m.wikipedia.org/wiki/2N3055 > The old slow klunky RCA 3055's were tough. Fairchild made a "2N3055" > that had a tiny chip, was very fast, and tended to blow up. > > > >Same likely goes for John Larkin's experiment, > >And manufacturers can change process any time, not something recommended to use out of spec. > That's a problem these days, getti9ng consistent parts, even from one > manufacturer. Data sheets don't tell the whole story and in fact try > to hide hazards. > > Sometimes, to get performance, you do what works. > > We need a web site, icbugs.com or something where people report parts > issues.Cool! I like it! Please start one now.
Reply by ●September 7, 20232023-09-07
On Thursday, September 7, 2023 at 9:48:42 AM UTC-7, John Larkin wrote:> >> >>>>> On 06/09/2023 01:04, John Larkin wrote: > >> >>>>>> Imagine an NPN transistor. Ground the emitter and connect the > >> >>>>>> collector to some nice positive voltage. > >> >>>>>> > >> >>>>>> Now pull the base negative, through a current-limiting resistor. What > >> >>>>>> happens?> ... I was thinking that my original quadrant comment could suggest > a mode where the b-e zener makes noise and the c-b junction amplifies > it. That depends on where the zener-inspired carriers go.Oh, that's obvious; breakdown of B-E is mainly dominated by carriers from the emitter, because there are so many of them (base is lightly doped). Those carriers are repelled by the collector (+ bias on collector, and emitter of NPN is shooting holes). Main effect I'd expect is aging of the surface, leading to base leakage if you ever revert the bias to normal transresistance operation.
Reply by ●September 8, 20232023-09-08
On 2023-09-06, piglet <erichpwagner@hotmail.com> wrote:> On 06/09/2023 01:04, John Larkin wrote: >> Imagine an NPN transistor. Ground the emitter and connect the >> collector to some nice positive voltage. >> >> Now pull the base negative, through a current-limiting resistor. What >> happens? >> > > If the collector is already positive and pullup resistor is not > extremely high then I think not much detectable will happen even once > the Veb junction breaks down. But if the collector is open circuit or > very lightly loaded then the collector should show that photo-electric > effect "the pease conundrum" we discussed back in 2015. Whereby the E-B > avalanching junction emits light that the C-B junction does a > photo-diode act on?but would the E-B reverse breakdown produce photons?> > piglet >-- Jasen. 🇺🇦 Слава Україні
Reply by ●September 9, 20232023-09-09
On Saturday, September 9, 2023 at 10:00:59 AM UTC+10, Jasen Betts wrote:> On 2023-09-06, piglet <erichp...@hotmail.com> wrote: > > On 06/09/2023 01:04, John Larkin wrote: > >> Imagine an NPN transistor. Ground the emitter and connect the > >> collector to some nice positive voltage. > >> > >> Now pull the base negative, through a current-limiting resistor. What > >> happens? > >> > > > > If the collector is already positive and pullup resistor is not > > extremely high then I think not much detectable will happen even once > > the Veb junction breaks down. But if the collector is open circuit or > > very lightly loaded then the collector should show that photo-electric > > effect "the pease conundrum" we discussed back in 2015. Whereby the E-B > > avalanching junction emits light that the C-B junction does a > > photo-diode act on? > > but would the E-B reverse breakdown produce photons?It always seems to. The packaging determines whether you can see them. There was a thread where the issue came up about a decade ago. mainly about whether zener diodes could oscillate - theye don't seem to - but avalanche diodes - anything that breaks down at much over 5V - can look as if that's what's going on. -- Bill Sloman, Sydney
Reply by ●September 9, 20232023-09-09
On 09/09/2023 00:46, Jasen Betts wrote:> On 2023-09-06, piglet <erichpwagner@hotmail.com> wrote: >> On 06/09/2023 01:04, John Larkin wrote: >>> Imagine an NPN transistor. Ground the emitter and connect the >>> collector to some nice positive voltage. >>> >>> Now pull the base negative, through a current-limiting resistor. What >>> happens? >>> >> >> If the collector is already positive and pullup resistor is not >> extremely high then I think not much detectable will happen even once >> the Veb junction breaks down. But if the collector is open circuit or >> very lightly loaded then the collector should show that photo-electric >> effect "the pease conundrum" we discussed back in 2015. Whereby the E-B >> avalanching junction emits light that the C-B junction does a >> photo-diode act on? > > but would the E-B reverse breakdown produce photons? > >> >> piglet >> > >Yes. Cut the top off a TO-18 or TO-5 metal can transistor and see for yourself! Back in fall 2015 we discussed this and I posted some photos. I cannot recall the current but I think was in the region of 10-20mA the light was clearly visible with ceiling lights off. To the eye it looked silvery-gray but the phone camera showed orange, maybe because there was a IR component to it? Robert Pease described the effect after seeing little speckles of light as op-amps were offset trimmed by the zener-zap technique (AFAIK an array of sacrificial junctions selectively zapped, a kind of anti-fuse, the zapped structure becoming a short). piglet
Reply by ●September 10, 20232023-09-10
On 06/09/2023 03:38, John Larkin wrote:> On Wed, 6 Sep 2023 02:31:04 -0000 (UTC), Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote: >>> On Wed, 6 Sep 2023 00:58:11 -0000 (UTC), Jasen Betts >>> <usenet@revmaps.no-ip.org> wrote: >>> >>>> On 2023-09-06, John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote: >>>>> Imagine an NPN transistor. Ground the emitter and connect the >>>>> collector to some nice positive voltage. >>>>> >>>>> Now pull the base negative, through a current-limiting resistor. What >>>>> happens? >>>> >>>> Nothing until you exceed the emitter base reverse breakdown (or >>>> collector base breakdown) voltage, >>> >>> Not literally nothing, but not much interesting. It gets more >>> interesting when the base zeners. >>> >>>> >>>> Bitter-base is usually about 5V >>>> >>>> Behaves kind of like a zener diode and damages the transistor. >>> >>> The base current is limited. But what happens? >>> >>> >> >> Haven’t tried it, at least not on purpose, but I’d guess that when the >> avalanche starts, most of the electrons will get sucked up by the >> collector. >> >> Since it’s the electrons and not the holes that do the avalanching in >> silicon, that might partially suppress the avalanche. If that were true, >> putting a positive voltage on the collector would make the base voltage >> slightly more negative. >> >> Cheers >> >> Phil Hobbs > > I'd expect that zenering fills the b-e junction with lots of carriers, > and some find their way into the collector. I don't know how many. > > Probably a lot less than foward base current. > > I suppose I should try it. >Did you try it? I did today with a junk box NPN and results are kind of as expected: <https://www.dropbox.com/scl/fi/rqr7n3uunosswqhx4e59h/NPNunusualQuadrant.pdf?rlkey=6kcqwz3soawgxws2ouhbdktq3&raw=1> piglet
Reply by ●September 10, 20232023-09-10
On Sunday, September 10, 2023 at 8:57:03 AM UTC-4, Piglet wrote:> On 06/09/2023 03:38, John Larkin wrote: > > On Wed, 6 Sep 2023 02:31:04 -0000 (UTC), Phil Hobbs > > <pcdhSpamM...@electrooptical.net> wrote: > > > >> John Larkin <jla...@highlandSNIPMEtechnology.com> wrote: > >>> On Wed, 6 Sep 2023 00:58:11 -0000 (UTC), Jasen Betts > >>> <use...@revmaps.no-ip.org> wrote: > >>> > >>>> On 2023-09-06, John Larkin <jla...@highlandSNIPMEtechnology.com> wrote: > >>>>> Imagine an NPN transistor. Ground the emitter and connect the > >>>>> collector to some nice positive voltage. > >>>>> > >>>>> Now pull the base negative, through a current-limiting resistor. What > >>>>> happens? > >>>> > >>>> Nothing until you exceed the emitter base reverse breakdown (or > >>>> collector base breakdown) voltage, > >>> > >>> Not literally nothing, but not much interesting. It gets more > >>> interesting when the base zeners. > >>> > >>>> > >>>> Bitter-base is usually about 5V > >>>> > >>>> Behaves kind of like a zener diode and damages the transistor. > >>> > >>> The base current is limited. But what happens? > >>> > >>> > >> > >> Haven’t tried it, at least not on purpose, but I’d guess that when the > >> avalanche starts, most of the electrons will get sucked up by the > >> collector. > >> > >> Since it’s the electrons and not the holes that do the avalanching in > >> silicon, that might partially suppress the avalanche. If that were true, > >> putting a positive voltage on the collector would make the base voltage > >> slightly more negative. > >> > >> Cheers > >> > >> Phil Hobbs > > > > I'd expect that zenering fills the b-e junction with lots of carriers, > > and some find their way into the collector. I don't know how many. > > > > Probably a lot less than foward base current. > > > > I suppose I should try it. > > > Did you try it? I did today with a junk box NPN and results are kind of > as expected: > > <https://www.dropbox.com/scl/fi/rqr7n3uunosswqhx4e59h/NPNunusualQuadrant.pdf?rlkey=6kcqwz3soawgxws2ouhbdktq3&raw=1>Does the collector current go through the base, or the emitter? -- Rick C. - Get 1,000 miles of free Supercharging - Tesla referral code - https://ts.la/richard11209
Reply by ●September 10, 20232023-09-10
On Sun, 10 Sep 2023 13:56:54 +0100, Piglet <erichpwagner@hotmail.com> wrote:>On 06/09/2023 03:38, John Larkin wrote: >> On Wed, 6 Sep 2023 02:31:04 -0000 (UTC), Phil Hobbs >> <pcdhSpamMeSenseless@electrooptical.net> wrote: >> >>> John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote: >>>> On Wed, 6 Sep 2023 00:58:11 -0000 (UTC), Jasen Betts >>>> <usenet@revmaps.no-ip.org> wrote: >>>> >>>>> On 2023-09-06, John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote: >>>>>> Imagine an NPN transistor. Ground the emitter and connect the >>>>>> collector to some nice positive voltage. >>>>>> >>>>>> Now pull the base negative, through a current-limiting resistor. What >>>>>> happens? >>>>> >>>>> Nothing until you exceed the emitter base reverse breakdown (or >>>>> collector base breakdown) voltage, >>>> >>>> Not literally nothing, but not much interesting. It gets more >>>> interesting when the base zeners. >>>> >>>>> >>>>> Bitter-base is usually about 5V >>>>> >>>>> Behaves kind of like a zener diode and damages the transistor. >>>> >>>> The base current is limited. But what happens? >>>> >>>> >>> >>> Haven�t tried it, at least not on purpose, but I�d guess that when the >>> avalanche starts, most of the electrons will get sucked up by the >>> collector. >>> >>> Since it�s the electrons and not the holes that do the avalanching in >>> silicon, that might partially suppress the avalanche. If that were true, >>> putting a positive voltage on the collector would make the base voltage >>> slightly more negative. >>> >>> Cheers >>> >>> Phil Hobbs >> >> I'd expect that zenering fills the b-e junction with lots of carriers, >> and some find their way into the collector. I don't know how many. >> >> Probably a lot less than foward base current. >> >> I suppose I should try it. >> > >Did you try it? I did today with a junk box NPN and results are kind of >as expected: > ><https://www.dropbox.com/scl/fi/rqr7n3uunosswqhx4e59h/NPNunusualQuadrant.pdf?rlkey=6kcqwz3soawgxws2ouhbdktq3&raw=1> > >pigletThat's cool. The effective beta is around 70u, less than I would have expected. Thanks. I'm still home recovering from a medical adventure, so I haven't tried it.
Reply by ●September 10, 20232023-09-10
On Monday, September 11, 2023 at 12:44:13 AM UTC+10, Ricky wrote:> On Sunday, September 10, 2023 at 8:57:03 AM UTC-4, Piglet wrote: > > On 06/09/2023 03:38, John Larkin wrote: > > > On Wed, 6 Sep 2023 02:31:04 -0000 (UTC), Phil Hobbs > > > <pcdhSpamM...@electrooptical.net> wrote: > > > > > >> John Larkin <jla...@highlandSNIPMEtechnology.com> wrote: > > >>> On Wed, 6 Sep 2023 00:58:11 -0000 (UTC), Jasen Betts > > >>> <use...@revmaps.no-ip.org> wrote: > > >>> > > >>>> On 2023-09-06, John Larkin <jla...@highlandSNIPMEtechnology.com> wrote: > > >>>>> Imagine an NPN transistor. Ground the emitter and connect the > > >>>>> collector to some nice positive voltage. > > >>>>> > > >>>>> Now pull the base negative, through a current-limiting resistor. What > > >>>>> happens? > > >>>> > > >>>> Nothing until you exceed the emitter base reverse breakdown (or > > >>>> collector base breakdown) voltage, > > >>> > > >>> Not literally nothing, but not much interesting. It gets more > > >>> interesting when the base zeners. > > >>> > > >>>> > > >>>> Bitter-base is usually about 5V > > >>>> > > >>>> Behaves kind of like a zener diode and damages the transistor. > > >>> > > >>> The base current is limited. But what happens? > > >>> > > >>> > > >> > > >> Haven’t tried it, at least not on purpose, but I’d guess that when the > > >> avalanche starts, most of the electrons will get sucked up by the > > >> collector. > > >> > > >> Since it’s the electrons and not the holes that do the avalanching in > > >> silicon, that might partially suppress the avalanche. If that were true, > > >> putting a positive voltage on the collector would make the base voltage > > >> slightly more negative. > > >> > > >> Cheers > > >> > > >> Phil Hobbs > > > > > > I'd expect that zenering fills the b-e junction with lots of carriers, > > > and some find their way into the collector. I don't know how many. > > > > > > Probably a lot less than foward base current. > > > > > > I suppose I should try it. > > > > > Did you try it? I did today with a junk box NPN and results are kind of > > as expected: > > > > <https://www.dropbox.com/scl/fi/rqr7n3uunosswqhx4e59h/NPNunusualQuadrant.pdf?rlkey=6kcqwz3soawgxws2ouhbdktq3&raw=1> > > Does the collector current go through the base, or the emitter?All of it goes through the base, but the bulk of it ends up in the emitter. That's how transistors work. -- Bill Sloman, Sydney
