Hi I agree with Chuck. I simply built a 2xAA battery holder with LM317 regulator to supply 1.35 v It works fine. Sent from my iPhone > On Jul 29, 2019, at 12:00 PM, volt-nuts-request@lists.febo.com wrote: > > Send volt-nuts mailing list submissions to > volt-nuts@lists.febo.com > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com > or, via email, send a message with subject or body 'help' to > volt-nuts-request@lists.febo.com > > You can reach the person managing the list at > volt-nuts-owner@lists.febo.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of volt-nuts digest..." > > > Today's Topics: > > 1. Stable reference battery (Victor Silva) > 2. Re: Stable reference battery (Chuck Harris) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 28 Jul 2019 22:53:07 -0400 > From: "Victor Silva" <daejon1@yahoo.com> > To: <volt-nuts@lists.febo.com> > Subject: [volt-nuts] Stable reference battery > Message-ID: <000a01d545b8$c0e68710$42b39530$@yahoo.com> > Content-Type: text/plain; charset="us-ascii" > > Have any volt-nuts refurbished a Fluke 540B and replaced the 1.35V Mercury > cell? > > > > I saw someone in Germany that used five AA NiMH cells in parallel to achieve > better stability than just one call. > > Has anyone invented the wheel already and looked into the Fluke solution (2 > AA with a 3 terminal regulator) vs > > 1. 5 NiMH in parallel > 2. 1 NiMH cell only > 3. Some NiMH calls with a stable reference device, rather than a > regulator. > > > > Thanks, > > Victor > > > > ------------------------------ > > Message: 2 > Date: Sun, 28 Jul 2019 23:45:20 -0400 > From: Chuck Harris <cfharris@erols.com> > To: Victor Silva via volt-nuts <volt-nuts@lists.febo.com> > Subject: Re: [volt-nuts] Stable reference battery > Message-ID: <02e753e8-60df-6659-bd73-056decfddb34@erols.com> > Content-Type: text/plain; charset=UTF-8 > > All of mine have a modification Fluke provided that replaces the > mercury D cell with two AA sized alkaline cells and a small circuit board > that has an adjustible LM317 3 terminal regulator set to make 1.35V. > > There is no need for the 1.35V to be all that stable, as it is just a > short term reference used with the galvanometer to transfer a DC value > that provides the same thermocouple response as the AC value being > measured. It is not like mercury cells were all that stable in the first > place, and the LM317 is much better. > > -Chuck Harris > > Victor Silva via volt-nuts wrote: >> Have any volt-nuts refurbished a Fluke 540B and replaced the 1.35V Mercury >> cell? >> >> >> >> I saw someone in Germany that used five AA NiMH cells in parallel to achieve >> better stability than just one call. >> >> Has anyone invented the wheel already and looked into the Fluke solution (2 >> AA with a 3 terminal regulator) vs >> >> 1. 5 NiMH in parallel >> 2. 1 NiMH cell only >> 3. Some NiMH calls with a stable reference device, rather than a >> regulator. >> >> >> >> Thanks, >> >> Victor >> >> _______________________________________________ >> volt-nuts mailing list -- volt-nuts@lists.febo.com >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com >> and follow the instructions there. >> > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > volt-nuts mailing list > volt-nuts@lists.febo.com > http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com > > > ------------------------------ > > End of volt-nuts Digest, Vol 117, Issue 13 > ******************************************