some breadboards
in [Design]
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From: brent on 8 Apr 2010 21:01 On Apr 8, 8:57 pm, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > On Thu, 08 Apr 2010 19:46:29 -0500, "k...(a)att.bizzzzzzzzzzzz" > > > > <k...(a)att.bizzzzzzzzzzzz> wrote: > >On Thu, 8 Apr 2010 17:12:33 -0700 (PDT), brent <buleg...(a)columbus.rr.com> > >wrote: > > >>On Apr 8, 8:10 pm, John Larkin > >><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >>>ftp://jjlarkin.lmi.net/BreadBoards.jpg > > >>>ftp://jjlarkin.lmi.net/BreadBoards2.JPG > > >>> John > > >>Are these your first pass board designs that you plan to put into > >>production? > > >Nice! ;-) > > If I test the parts I don't fully understand, the products will work > first pass. *That* is nice. > > A breadboard is not a prototype. It's a way to better understand a > part. The "circuit" of such a breadboard is unlikely to appear in any > deliverable product. > > John First pass design means first pass design. This should all be modeled and you should not be wasting someones time to build these boards when a handy dandy simulator program is available. OK - I'm just ribbing you. You obviously know your business and how to most effectively get to production, but on size does not fit all in electrical design.
From: krw on 8 Apr 2010 21:09 On Thu, 08 Apr 2010 17:57:40 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 08 Apr 2010 19:46:29 -0500, "krw(a)att.bizzzzzzzzzzzz" ><krw(a)att.bizzzzzzzzzzzz> wrote: > >>On Thu, 8 Apr 2010 17:12:33 -0700 (PDT), brent <bulegoge(a)columbus.rr.com> >>wrote: >> >>>On Apr 8, 8:10�pm, John Larkin >>><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>>> ftp://jjlarkin.lmi.net/BreadBoards.jpg >>>> >>>> ftp://jjlarkin.lmi.net/BreadBoards2.JPG >>>> >>>> John >>> >>>Are these your first pass board designs that you plan to put into >>>production? >> >>Nice! ;-) > >If I test the parts I don't fully understand, the products will work >first pass. *That* is nice. >A breadboard is not a prototype. It's a way to better understand a >part. The "circuit" of such a breadboard is unlikely to appear in any >deliverable product. Just bustin' your chops, John. I'm on your side in that kerfuffle (though don't often come up to your standards), but funny is funny.
From: John Larkin on 8 Apr 2010 21:16 On Thu, 8 Apr 2010 18:01:57 -0700 (PDT), brent <bulegoge(a)columbus.rr.com> wrote: >On Apr 8, 8:57�pm, John Larkin ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> On Thu, 08 Apr 2010 19:46:29 -0500, "k...(a)att.bizzzzzzzzzzzz" >> >> >> >> <k...(a)att.bizzzzzzzzzzzz> wrote: >> >On Thu, 8 Apr 2010 17:12:33 -0700 (PDT), brent <buleg...(a)columbus.rr.com> >> >wrote: >> >> >>On Apr 8, 8:10�pm, John Larkin >> >><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>ftp://jjlarkin.lmi.net/BreadBoards.jpg >> >> >>>ftp://jjlarkin.lmi.net/BreadBoards2.JPG >> >> >>> John >> >> >>Are these your first pass board designs that you plan to put into >> >>production? >> >> >Nice! ;-) >> >> If I test the parts I don't fully understand, the products will work >> first pass. *That* is nice. >> >> A breadboard is not a prototype. It's a way to better understand a >> part. The "circuit" of such a breadboard is unlikely to appear in any >> deliverable product. >> >> John > >First pass design means first pass design. This should all be modeled >and you should not be wasting someones time to build these boards when >a handy dandy simulator program is available. You can't usefully simulate a system without good part models, and lots of parts have no or bad models. Especially RF parts used in nonlinear or time-domain apps. > >OK - I'm just ribbing you. You obviously know your business and how >to most effectively get to production, but on size does not fit all in >electrical design. I like soldering and playing with parts once in a while, and blowing things up. When we make measurements like this, we write it up (or just photograph the breadboards/notes/whiteboards) and add it to the datasheets and stuff we keep in our parts database. So we don't lose it. What's tricky is to decide how far you might go beyond a part's published specs, or how to make you own limits from measurements when there aren't suitable specs. 1206 resistor at 26 watts for 1 millisecond! John
From: brent on 8 Apr 2010 21:29 On Apr 8, 9:16 pm, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > On Thu, 8 Apr 2010 18:01:57 -0700 (PDT), brent > > > > <buleg...(a)columbus.rr.com> wrote: > >On Apr 8, 8:57 pm, John Larkin > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >> On Thu, 08 Apr 2010 19:46:29 -0500, "k...(a)att.bizzzzzzzzzzzz" > > >> <k...(a)att.bizzzzzzzzzzzz> wrote: > >> >On Thu, 8 Apr 2010 17:12:33 -0700 (PDT), brent <buleg...(a)columbus.rr.com> > >> >wrote: > > >> >>On Apr 8, 8:10 pm, John Larkin > >> >><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >> >>>ftp://jjlarkin.lmi.net/BreadBoards.jpg > > >> >>>ftp://jjlarkin.lmi.net/BreadBoards2.JPG > > >> >>> John > > >> >>Are these your first pass board designs that you plan to put into > >> >>production? > > >> >Nice! ;-) > > >> If I test the parts I don't fully understand, the products will work > >> first pass. *That* is nice. > > >> A breadboard is not a prototype. It's a way to better understand a > >> part. The "circuit" of such a breadboard is unlikely to appear in any > >> deliverable product. > > >> John > > >First pass design means first pass design. This should all be modeled > >and you should not be wasting someones time to build these boards when > >a handy dandy simulator program is available. > > You can't usefully simulate a system without good part models, and > lots of parts have no or bad models. Especially RF parts used in > nonlinear or time-domain apps. > > > > >OK - I'm just ribbing you. You obviously know your business and how > >to most effectively get to production, but on size does not fit all in > >electrical design. > > I like soldering and playing with parts once in a while, and blowing > things up. When we make measurements like this, we write it up (or > just photograph the breadboards/notes/whiteboards) and add it to the > datasheets and stuff we keep in our parts database. So we don't lose > it. > > What's tricky is to decide how far you might go beyond a part's > published specs, or how to make you own limits from measurements when > there aren't suitable specs. > > 1206 resistor at 26 watts for 1 millisecond! > > John Where we got burned years ago was using 1206 resistors in high peak power very low duty cycle applications. The average power dissipation was well within spec, but the peak voltages were ruining the resistors. (Domain Knowledge learned the hard way)
From: John Larkin on 8 Apr 2010 22:23
On Thu, 8 Apr 2010 18:29:33 -0700 (PDT), brent <bulegoge(a)columbus.rr.com> wrote: >On Apr 8, 9:16�pm, John Larkin ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> On Thu, 8 Apr 2010 18:01:57 -0700 (PDT), brent >> >> >> >> <buleg...(a)columbus.rr.com> wrote: >> >On Apr 8, 8:57�pm, John Larkin >> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> >> On Thu, 08 Apr 2010 19:46:29 -0500, "k...(a)att.bizzzzzzzzzzzz" >> >> >> <k...(a)att.bizzzzzzzzzzzz> wrote: >> >> >On Thu, 8 Apr 2010 17:12:33 -0700 (PDT), brent <buleg...(a)columbus.rr.com> >> >> >wrote: >> >> >> >>On Apr 8, 8:10�pm, John Larkin >> >> >><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> >> >>>ftp://jjlarkin.lmi.net/BreadBoards.jpg >> >> >> >>>ftp://jjlarkin.lmi.net/BreadBoards2.JPG >> >> >> >>> John >> >> >> >>Are these your first pass board designs that you plan to put into >> >> >>production? >> >> >> >Nice! ;-) >> >> >> If I test the parts I don't fully understand, the products will work >> >> first pass. *That* is nice. >> >> >> A breadboard is not a prototype. It's a way to better understand a >> >> part. The "circuit" of such a breadboard is unlikely to appear in any >> >> deliverable product. >> >> >> John >> >> >First pass design means first pass design. �This should all be modeled >> >and you should not be wasting someones time to build these boards when >> >a handy dandy simulator program is available. >> >> You can't usefully simulate a system without good part models, and >> lots of parts have no or bad models. Especially RF parts used in >> nonlinear or time-domain apps. >> >> >> >> >OK - I'm just ribbing you. �You obviously know your business and how >> >to most effectively get to production, but on size does not fit all in >> >electrical design. >> >> I like soldering and playing with parts once in a while, and blowing >> things up. When we make measurements like this, we write it up (or >> just photograph the breadboards/notes/whiteboards) and add it to the >> datasheets and stuff we keep in our parts database. So we don't lose >> it. >> >> What's tricky is to decide how far you might go beyond a part's >> published specs, or how to make you own limits from measurements when >> there aren't suitable specs. >> >> 1206 resistor at 26 watts for 1 millisecond! >> >> John > >Where we got burned years ago was using 1206 resistors in high peak >power very low duty cycle applications. The average power dissipation >was well within spec, but the peak voltages were ruining the >resistors. (Domain Knowledge learned the hard way) My case is just for an overload rating for the 4-20 mA i/o channel thing we're doing. We're specifying that the customer can apply up to 50 volts across our pins without damaging it. We of course hope nobody ever will. The resistors will dissipate about 26 watts, and the supervisory CPU should shut off a series SSR in a couple of hundred microseconds. The resistors explode at 65 watts in 1 millisecond, pulsed at 1 Hz, so we have a pretty decent margin. The 50 volts is arbitrary, just based on what we think is safe. We could spec it at 40 if we wanted. Time to cook some salmon cakes. John |