BC337 hfe distribution
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From: Hammy on 9 Apr 2010 19:35 On Fri, 9 Apr 2010 15:57:28 -0700, "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in >message news:ucavr5hlkgrvich7dm596kvhn56riofd0f(a)4ax.com... >> You mean none that you recognize. > >Right -- essentially the first BJT model you encounter in school. > >I realize that while this is a good enough model to design, I dunno, audio >amplifiers or oscillators and maybe get a start on a 741, anyone doing >BJT-based design today (at least for money :-) ) is using far more >sophisticated models that do rely heavily on the actual device parameters. > I wouldnt waste your time. Transistors will be obsolete according to HP. ;-) I never heard of this (memristors)? "Hewlett-Packard scientists on Thursday are to report advances in the design of a new class of diminutive switches capable of replacing transistors as computer chips shrink closer to the atomic scale. " http://www.nytimes.com/2010/04/08/science/08chips.html "The most advanced transistor technology today is based on minimum feature sizes of 30 to 40 nanometers � by contrast a biological virus is typically about 100 nanometers � and Dr. Williams said that H.P. now has working 3-nanometer memristors that can switch on and off in about a nanosecond, or a billionth of a second. "
From: Tim Williams on 9 Apr 2010 20:46 "Hammy" <spam(a)spam.com> wrote in message news:o6evr5t12h4qqat3cfmkeqm1abaem8slie(a)4ax.com... > "The most advanced transistor technology today is based on minimum > feature sizes of 30 to 40 nanometers � by contrast a biological virus > is typically about 100 nanometers � and Dr. Williams said that H.P. > now has working 3-nanometer memristors that can switch on and off in > about a nanosecond, or a billionth of a second. " Wow, that's slow. I have 2N3904s that avalanche faster than that! 'Course, they're referring to the memristance effect, which is fundamentally different. When it comes to moving ions in a crystal, that's not too bad. Heh...speaking of moving ions... wouldn't the gate threshold voltage hysteresis of sodium impurities have a similar effect? But since it's on a gate, it would be more of a transmemristance effect? :-) I wonder if a couple sodium ions buried into a regular DRAM cell could have any useful effect. (Note it's probably a good idea to deposit sodium only in the active cells, and not the word line switches...) Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms
From: Paul Keinanen on 10 Apr 2010 00:32 On Fri, 09 Apr 2010 21:25:45 +0100, John Devereux <john(a)devereux.me.uk> wrote: >"E" <invalid(a)invalid.invalid> writes: > >> "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> kirjoitti >> viestiss�:fmLvn.199280$rq1.66072(a)en-nntp-02.dc1.easynews.com... >>> "E" <invalid(a)invalid.invalid> wrote in message >>> news:hpnv2c$5it$1(a)news.eternal-september.org... >>>> Distribution is a bit strange looking with two spikes >>> >>> Maybe two different batches of parts? >>> >> >> Possibly, alltought they were all from same bag. >> Or maybe just from different wafers? >> How many BC337 fit one wafer? Probably quite many... >> >> -ek >> >> > >Perhaps they take all the middle ones for a tighter-spec version? In Europe, traditionally a letter is appended at the end of the type designator to signify the current gain group. If you specify just "BC337", it is quite possible that transistors belonging to a specific group may have been taken out. In a similar way, if you order 5 or 10 % resistors/capacitors, there might be deep dips in the distribution close to the nominal E12/E24 values, as these are selected out and sold as 1 % components.
From: Helmut Sennewald on 10 Apr 2010 08:23 "E" <invalid(a)invalid.invalid> schrieb im Newsbeitrag news:hpnv2c$5it$1(a)news.eternal-september.org... > Just measured hfe from some BC337-40 at about 5 mA collector current. > Unfortunately nothing very interesting there > > Results: > Sample size: 960 pcs > minimum hfe: 388 > maximum hfe 513 > (datasheet limits are 250 and 630) > avarage: 452 > avarage deviation: 27 > median: 463 > mode: 477 > Distribution is a bit strange looking with two spikes > Histogram here: http://koti.mbnet.fi/hsahko/hfe/ > > -ek Hello ek, Have you measured half of the transistors on the other day when the room temperature was a few degrees different? Current gain of transistors heavily depends on temperature. Best regards, Helmut
From: E on 10 Apr 2010 10:10
"Helmut Sennewald" <helmutsennewald(a)t-online.de> kirjoitti viestiss�:hppqkr$hm6$03$1(a)news.t-online.com... > "E" <invalid(a)invalid.invalid> schrieb im Newsbeitrag > news:hpnv2c$5it$1(a)news.eternal-september.org... >> Just measured hfe from some BC337-40 at about 5 mA collector current. >> Unfortunately nothing very interesting there >> >> Results: >> Sample size: 960 pcs >> minimum hfe: 388 >> maximum hfe 513 >> (datasheet limits are 250 and 630) >> avarage: 452 >> avarage deviation: 27 >> median: 463 >> mode: 477 >> Distribution is a bit strange looking with two spikes >> Histogram here: http://koti.mbnet.fi/hsahko/hfe/ >> >> -ek > > Hello ek, > > Have you measured half of the transistors on the other day when the > room temperature was a few degrees different? > Current gain of transistors heavily depends on temperature. > > Best regards, > Helmut > > No, they are all measured within three hours. I just looked at the data file in 250 pcs slices and distribution looks about same in each slice. -ek |