[volt-nuts] Matched resistors
Randy, resistor matched in T.C. are extremely expensive, as the manufacturer (or yourself) would have to select these from a batch of many samples. reistors with very small T.C. (<1ppm/K) would do the job also, but they also need to be stable over time, in shelf life opereation mode, i.e. P<10mW. That means, you need those hermetically sealed VHP202Z from Vishay, T.C. is typically < 1ppm/K and they are stable to < 2ppm over 5years. But they cost already 80€ each, depending on tolerance. I made a longterm observation of these and found these parameters confirmed. Frank ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Matched resistors
Hi Randy; I would look at Visha Foil resistors http://www.vishaypg.com/docs/63120/hzseries.pdf Hope that helps. Cheers; Thomas Knox > Date: Wed, 16 Jul 2014 17:44:10 -0700 > From: randyevans2...@gmail.com > To: volt-nuts@febo.com > Subject: [volt-nuts] Matched resistors > > I am building a 10V voltage reference based on the LTZ1000 and the design > is essentially done but I am looking for a pair of matched resistors that > track very closely over temperature. The absolute value of the pair is not > important, anything between 50K and 200K ohms would be ideal, but the > matching ratio is very important. > > I looked at the 100K ohm LT5400 quad resistor array from Linear Technology > but it has a worst case long term accelerated shelf life spec of 10 ppm (at > 150C) matching ratio and long term matching ratio drift of <4ppm (at 70C). > I would like something much tighter if possible since that would mean I > likely don't need an oven for a couple of ppm worst case accuracy over time > and temperature. I can make the LT5400 work but I would need to do > temperature characterization and circuit compensation. Doable but > undesirable. > > Does anyone have any ideas for a good ratio matched resistor pair, > hopefully not too expensive? > > Thanks, > > Randy Evans > ___ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
[volt-nuts] Matched resistors
I am building a 10V voltage reference based on the LTZ1000 and the design is essentially done but I am looking for a pair of matched resistors that track very closely over temperature. The absolute value of the pair is not important, anything between 50K and 200K ohms would be ideal, but the matching ratio is very important. I looked at the 100K ohm LT5400 quad resistor array from Linear Technology but it has a worst case long term accelerated shelf life spec of 10 ppm (at 150C) matching ratio and long term matching ratio drift of <4ppm (at 70C). I would like something much tighter if possible since that would mean I likely don't need an oven for a couple of ppm worst case accuracy over time and temperature. I can make the LT5400 work but I would need to do temperature characterization and circuit compensation. Doable but undesirable. Does anyone have any ideas for a good ratio matched resistor pair, hopefully not too expensive? Thanks, Randy Evans ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Desperately seeking OPTION 10 for Datron 4708
Chris, I am aware that Low Thermal Low Electronics www.lowthermal.com/wavetek-datron/470x.php does specialise in the repair of older calibrator in particular Datron Wavetek. I did query them at one stage about there spares situation and they did say they did have or could source spares for most Datron meters and calibrators. I image that their prices will not be cheap but they may be worth a try if you are desparate. I have no relationship with Low Thermal I have just being a satisfied customer in the past. Kind Regards, Stephen Grady Sydney Australia -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Chris Sent: Wednesday, 16 July 2014 10:48 PM To: volt-nuts@febo.com Subject: Re: [volt-nuts] Desperately seeking OPTION 10 for Datron 4708 Thank you for the bad news :( I am starting to come to terms with the difficulty of finding this option. I have recently discovered that option 10 from the 4700, 4705, and 4707 would also work. Not sure if this makes it any easier. Also my unit has a sticker on the front indicating "ac voltage and current only"... But lists options 20,30,80,90 on the backside label. Will my unit have resistance functionality? I am hearing a lot of conflicting information. Not sure if I am replying to emails correctly. (New to volt nuts) On Jul 12, 2014 6:03 PM, "Chris" wrote: > Nobody has access to spare Datron 4708 stuff? I am willing to pay > international shipping etc... whatever it takes! Thank you > > > On Thu, Jul 10, 2014 at 2:09 PM, Chris wrote: > >> I am looking to purchase OPTION 10 slide in board for the Datron 4708 >> Multifunction Calibrator. If anybody has a parted out unit and can >> sell me just the option 10 board i would appreciate it dearly! Thank >> you for considering! >> >> Chris >> > > ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Desperately seeking OPTION 10 for Datron 4708
I don't have access to the schematics right now. For the DC section, I would think that the selected reference array would be the only difference. The firmware will dictate the model. I have not compared the option 10 board in the 4700 to the 4000A but I think there will be little difference there too. I cannot remember if I have the 4000A schematics but I think they are online. I think the resistance/shunt board would be the same. There were slight differences in specs but I don't think they made any layout changes that couldn't be modified. I have an old 4000A waiting for me to repair it. I have looked at the resistance/shunt board and I can tell that there are some bodges to the trim pots. I have not measured any of the affected resistors, but I am guessing they have drifted out of the trimmable range since additional resistors were added to the board. Todd On Wed, Jul 16, 2014 at 2:38 PM, Tom Knox wrote: > I wonder if the tolerances are different on option 10 boards in the > series? If so it could makes the board much easier to find. The service > manuals would confirm interchangeability if the part numbers are the same, > but even if the 4708 uses selected parts, most components stability improve > with age and so if the topography is the same you should be good to go. > > Thomas Knox > > > Luck is preparation waiting to happen. > > > From: tmical...@gmail.com > > Date: Wed, 16 Jul 2014 10:29:43 -0400 > > To: volt-nuts@febo.com > > Subject: Re: [volt-nuts] Desperately seeking OPTION 10 for Datron 4708 > > > > Chris, > > > > I believe the current and resistance functions are on the same board. My > 4700 is missing one board and it has both missing features. > > > > Todd > > > > Sent from my iPad > > > > > On Jul 16, 2014, at 8:48, Chris wrote: > > > > > > Thank you for the bad news :( I am starting to come to terms with the > > > difficulty of finding this option. I have recently discovered that > option > > > 10 from the 4700, 4705, and 4707 would also work. Not sure if this > makes it > > > any easier. > > > > > > Also my unit has a sticker on the front indicating "ac voltage and > current > > > only"... But lists options 20,30,80,90 on the backside label. Will my > unit > > > have resistance functionality? I am hearing a lot of conflicting > > > information. > > > > > > Not sure if I am replying to emails correctly. (New to volt nuts) > > >> On Jul 12, 2014 6:03 PM, "Chris" wrote: > > >> > > >> Nobody has access to spare Datron 4708 stuff? I am willing to pay > > >> international shipping etc... whatever it takes! Thank you > > >> > > >> > > >>> On Thu, Jul 10, 2014 at 2:09 PM, Chris wrote: > > >>> > > >>> I am looking to purchase OPTION 10 slide in board for the Datron 4708 > > >>> Multifunction Calibrator. If anybody has a parted out unit and can > sell me > > >>> just the option 10 board i would appreciate it dearly! Thank you for > > >>> considering! > > >>> > > >>> Chris > > > ___ > > > volt-nuts mailing list -- volt-nuts@febo.com > > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > > and follow the instructions there. > > ___ > > volt-nuts mailing list -- volt-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > ___ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Desperately seeking OPTION 10 for Datron 4708
I wonder if the tolerances are different on option 10 boards in the series? If so it could makes the board much easier to find. The service manuals would confirm interchangeability if the part numbers are the same, but even if the 4708 uses selected parts, most components stability improve with age and so if the topography is the same you should be good to go. Thomas Knox Luck is preparation waiting to happen. > From: tmical...@gmail.com > Date: Wed, 16 Jul 2014 10:29:43 -0400 > To: volt-nuts@febo.com > Subject: Re: [volt-nuts] Desperately seeking OPTION 10 for Datron 4708 > > Chris, > > I believe the current and resistance functions are on the same board. My 4700 > is missing one board and it has both missing features. > > Todd > > Sent from my iPad > > > On Jul 16, 2014, at 8:48, Chris wrote: > > > > Thank you for the bad news :( I am starting to come to terms with the > > difficulty of finding this option. I have recently discovered that option > > 10 from the 4700, 4705, and 4707 would also work. Not sure if this makes it > > any easier. > > > > Also my unit has a sticker on the front indicating "ac voltage and current > > only"... But lists options 20,30,80,90 on the backside label. Will my unit > > have resistance functionality? I am hearing a lot of conflicting > > information. > > > > Not sure if I am replying to emails correctly. (New to volt nuts) > >> On Jul 12, 2014 6:03 PM, "Chris" wrote: > >> > >> Nobody has access to spare Datron 4708 stuff? I am willing to pay > >> international shipping etc... whatever it takes! Thank you > >> > >> > >>> On Thu, Jul 10, 2014 at 2:09 PM, Chris wrote: > >>> > >>> I am looking to purchase OPTION 10 slide in board for the Datron 4708 > >>> Multifunction Calibrator. If anybody has a parted out unit and can sell me > >>> just the option 10 board i would appreciate it dearly! Thank you for > >>> considering! > >>> > >>> Chris > > ___ > > volt-nuts mailing list -- volt-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > ___ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Desperately seeking OPTION 10 for Datron 4708
Chris, I believe the current and resistance functions are on the same board. My 4700 is missing one board and it has both missing features. Todd Sent from my iPad > On Jul 16, 2014, at 8:48, Chris wrote: > > Thank you for the bad news :( I am starting to come to terms with the > difficulty of finding this option. I have recently discovered that option > 10 from the 4700, 4705, and 4707 would also work. Not sure if this makes it > any easier. > > Also my unit has a sticker on the front indicating "ac voltage and current > only"... But lists options 20,30,80,90 on the backside label. Will my unit > have resistance functionality? I am hearing a lot of conflicting > information. > > Not sure if I am replying to emails correctly. (New to volt nuts) >> On Jul 12, 2014 6:03 PM, "Chris" wrote: >> >> Nobody has access to spare Datron 4708 stuff? I am willing to pay >> international shipping etc... whatever it takes! Thank you >> >> >>> On Thu, Jul 10, 2014 at 2:09 PM, Chris wrote: >>> >>> I am looking to purchase OPTION 10 slide in board for the Datron 4708 >>> Multifunction Calibrator. If anybody has a parted out unit and can sell me >>> just the option 10 board i would appreciate it dearly! Thank you for >>> considering! >>> >>> Chris > ___ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Desperately seeking OPTION 10 for Datron 4708
Thank you for the bad news :( I am starting to come to terms with the difficulty of finding this option. I have recently discovered that option 10 from the 4700, 4705, and 4707 would also work. Not sure if this makes it any easier. Also my unit has a sticker on the front indicating "ac voltage and current only"... But lists options 20,30,80,90 on the backside label. Will my unit have resistance functionality? I am hearing a lot of conflicting information. Not sure if I am replying to emails correctly. (New to volt nuts) On Jul 12, 2014 6:03 PM, "Chris" wrote: > Nobody has access to spare Datron 4708 stuff? I am willing to pay > international shipping etc... whatever it takes! Thank you > > > On Thu, Jul 10, 2014 at 2:09 PM, Chris wrote: > >> I am looking to purchase OPTION 10 slide in board for the Datron 4708 >> Multifunction Calibrator. If anybody has a parted out unit and can sell me >> just the option 10 board i would appreciate it dearly! Thank you for >> considering! >> >> Chris >> > > ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
