I forgot to mention that I also own a PPM Inc. Model AVM-100 null meter. Works great on AC but I need to replace the NiCd batteries for it to work on batteries. It has a 1uV scale, and it is a bit noisy on that scale. I intend to modify it to get batter 1/f noise specs on the 1uV scale. Does anyone know where I can get [or how to make] a low-thermal-EMF switch [or relay]? This would need to be a DPDT type to be able to reverse the connection to the meter. Ideas?

A Data Proof scanner seems to be the standard of some primary labs. They don't show up often on the auction site. This company makes one that fits the front of a 732B. I have never seen it in use. http://www.hpd-online.com/reversing_switch.php There also appears to be a Guildline 9600 up for auction. It is misspelled Guideline. I don't know the specs of that item, I have just noticed it has been listed for a while. Some of the Keithley instruments take "low thermal" cards, but they are not reversible as far as I can tell. You might be able to do so with two separate inputs. It is a Keithley 7168 nanovolt scanner card. If you can get one, I am pretty sure you can plug it into a 7001/7002 scanner. A home made switch might be cheaper if you can source some good low thermal latching relays. Todd On Wed, Feb 11, 2015 at 12:35 PM, Ken Peek <ken.peek@diligentminds.com> wrote: > I forgot to mention that I also own a PPM Inc. Model AVM-100 null meter. > Works great on AC but I need to replace the NiCd batteries for it to > work on batteries. It has a 1uV scale, and it is a bit noisy on that > scale. I intend to modify it to get batter 1/f noise specs on the 1uV > scale. > > Does anyone know where I can get [or how to make] a low-thermal-EMF > switch [or relay]? This would need to be a DPDT type to be able to > reverse the connection to the meter. Ideas? > > _______________________________________________ > 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. >

The most noiseless and stable nullmeter is any of the EM Electronics nanovoltmeter. Even the oldest EM N1a I have, gives about 1 nV p-p noise and <1 pA input current. Regards, Mickle KP> _______________________________________________ KP> volt-nuts mailing list -- volt-nuts@febo.com KP> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts KP> and follow the instructions there.

Dear Ken Peek, I designed a powerless automatic 2*4 low thermal EMF switch for 3458A, 34401A and 34420A(works also on my R6581T and 1281). It performs great and I use it as my main comparison tool for 10V and 10k standards. http://bbs.38hot.net/thread-1186-1-1.html lymex/bg2vo >-----邮件原件----- >发件人: volt-nuts [mailto:volt-nuts-bounces@febo.com] 代表 Ken Peek >发送时间: 2015年2月12日 1:35 >收件人: volt-nuts@febo.com >主题: Re: [volt-nuts] Calibration of voltage standards > >I forgot to mention that I also own a PPM Inc. Model AVM-100 null meter. >Works great on AC but I need to replace the NiCd batteries for it to >work on batteries. It has a 1uV scale, and it is a bit noisy on that >scale. I intend to modify it to get batter 1/f noise specs on the 1uV >scale. > >Does anyone know where I can get [or how to make] a low-thermal-EMF >switch [or relay]? This would need to be a DPDT type to be able to >reverse the connection to the meter. Ideas? > >_______________________________________________ >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.

On 13/02/2015 01:40, 张利民 wrote: > Dear Ken Peek, > I designed a powerless automatic 2*4 low thermal EMF switch for 3458A, 34401A and 34420A(works also on my R6581T and 1281). It performs great and I use it as my main comparison tool for 10V and 10k standards. > http://bbs.38hot.net/thread-1186-1-1.html > lymex/bg2vo > >> -----邮件原件----- >> 发件人: volt-nuts [mailto:volt-nuts-bounces@febo.com] 代表 Ken Peek >> 发送时间: 2015年2月12日 1:35 >> 收件人: volt-nuts@febo.com >> 主题: Re: [volt-nuts] Calibration of voltage standards >> >> I forgot to mention that I also own a PPM Inc. Model AVM-100 null meter. >> Works great on AC but I need to replace the NiCd batteries for it to >> work on batteries. It has a 1uV scale, and it is a bit noisy on that >> scale. I intend to modify it to get batter 1/f noise specs on the 1uV >> scale. >> >> Does anyone know where I can get [or how to make] a low-thermal-EMF >> switch [or relay]? This would need to be a DPDT type to be able to >> reverse the connection to the meter. Ideas? Hi Lymex, Great idea. I will have to spend some time looking over the google translate version of your text, as unfortunately it seems that here in the United Kingdom we cannot see any in line images from 38hot. I guess I would have to sign up to see them? And even the video of your box would not stream for me.

Hi M K, Sorry about that, I have posted a new thread on EEVBLOG with added photos. http://www.eevblog.com/forum/projects/diy-low-thermal-emf-switchscanner-for-comparisons-of-voltage-and-resistor-stand/ lymex/bg2vo >-----邮件原件----- >发件人: volt-nuts [mailto:volt-nuts-bounces@febo.com] 代表 M K >发送时间: 2015年2月13日 14:45 >收件人: volt-nuts@febo.com >主题: Re: [volt-nuts] Calibration of voltage standards >On 13/02/2015 01:40, 张利民 wrote: >> Dear Ken Peek, >> I designed a powerless automatic 2*4 low thermal EMF switch for 3458A, 34401A and 34420A(works also on my R6581T and 1281). It performs great and I use it as my main comparison tool for 10V and 10k standards. >> http://bbs.38hot.net/thread-1186-1-1.html > lymex/bg2vo >> >>> -----邮件原件----- >>> 发件人: volt-nuts [mailto:volt-nuts-bounces@febo.com] 代表 Ken Peek >>> 发送时间: 2015年2月12日 1:35 >>> 收件人: volt-nuts@febo.com >>> 主题: Re: [volt-nuts] Calibration of voltage standards >>> >>> I forgot to mention that I also own a PPM Inc. Model AVM-100 null meter. >>> Works great on AC but I need to replace the NiCd batteries for it to >>> work on batteries. It has a 1uV scale, and it is a bit noisy on that >>> scale. I intend to modify it to get batter 1/f noise specs on the 1uV >>> scale. >>> >>> Does anyone know where I can get [or how to make] a low-thermal-EMF >>> switch [or relay]? This would need to be a DPDT type to be able to >>> reverse the connection to the meter. Ideas? >Hi Lymex, > >Great idea. I will have to spend some time looking over the google >translate version of your text, as unfortunately it seems that here in >the United Kingdom we cannot see any in line images from 38hot. I guess >I would have to sign up to see them? And even the video of your box >would not stream for me. > > >_______________________________________________ >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.

On 16/02/2015 06:45, 张利民 wrote: > Hi M K, > > Sorry about that, I have posted a new thread on EEVBLOG with added photos. > http://www.eevblog.com/forum/projects/diy-low-thermal-emf-switchscanner-for-comparisons-of-voltage-and-resistor-stand/ > > lymex/bg2vo > >> -----邮件原件----- >> 发件人: volt-nuts [mailto:volt-nuts-bounces@febo.com] 代表 M K >> 发送时间: 2015年2月13日 14:45 >> 收件人: volt-nuts@febo.com >> 主题: Re: [volt-nuts] Calibration of voltage standards >> On 13/02/2015 01:40, 张利民 wrote: >>> Dear Ken Peek, >>> I designed a powerless automatic 2*4 low thermal EMF switch for 3458A, 34401A and 34420A(works also on my R6581T and 1281). It performs great and I use it as my main comparison tool for 10V and 10k standards. >>> http://bbs.38hot.net/thread-1186-1-1.html >> lymex/bg2vo >>>> -----邮件原件----- >>>> 发件人: volt-nuts [mailto:volt-nuts-bounces@febo.com] 代表 Ken Peek >>>> 发送时间: 2015年2月12日 1:35 >>>> 收件人: volt-nuts@febo.com >>>> 主题: Re: [volt-nuts] Calibration of voltage standards >>>> >>>> I forgot to mention that I also own a PPM Inc. Model AVM-100 null meter. >>>> Works great on AC but I need to replace the NiCd batteries for it to >>>> work on batteries. It has a 1uV scale, and it is a bit noisy on that >>>> scale. I intend to modify it to get batter 1/f noise specs on the 1uV >>>> scale. >>>> >>>> Does anyone know where I can get [or how to make] a low-thermal-EMF >>>> switch [or relay]? This would need to be a DPDT type to be able to >>>> reverse the connection to the meter. Ideas? >> Hi Lymex, >> >> Great idea. I will have to spend some time looking over the google >> translate version of your text, as unfortunately it seems that here in >> the United Kingdom we cannot see any in line images from 38hot. I guess >> I would have to sign up to see them? And even the video of your box >> would not stream for me. Hi Lymex, Amazing lab you have there. Thanks. M K