You can add an voltage follower. Made one using a LT1052 and LT1010 ( if i have the number right, a power opamp) the design is from Williams, he uses it in is his sub 1ppm reference. I use it to buffer the 731A, that is less stable as my home made LM399, that is getting more stable every week. I monitor rH% and temp and as temp goes down and rH% goes up I get the biggest jumps ( around 40-50 uV) if is to soon to be sure but it looks like rH% has a bigger influence as temperature. The monitoring Solartron 7061 is modified to be kept at 39 degrees by cooling it from the outside and measuring temp inside. ( http://www.pa4tim.nl/?p=2456 ) see picture doen the page ( temp is not yet at 39 degrees there) the fan allways blows, it just goes faster when hot and slower when cold so I do not get temp jumps ( bang-bang regulation like Williams called it)
Fred PA4TIM Op 27 nov. 2012 om 00:27 heeft Bob Smither <[email protected]> het volgende geschreven: > The 731A is specified to have an output impedance of less than 1.1K in the 10V > setting. A meter with 10 M input Z therefore causes a .01% (100 ppm) reading > error. > > I understand that when operated using a null meter the output impedance is > not a > problem. I would like to use my 731A as a bench standard for my DMMs. > > The 10V output is taken through a 1K resistor (R18) from the output pin of the > op-amp. Clearly the op-amp output pin is much lower impedance. > > The op-amp is an LM301A and appears to be conservatively compensated. > > I am thinking of shorting R18. I understand it provides some protection to > the > op-amp and may be a factor in the op-amp stability. > > Other than the above, can anyone see why this would be a bad idea? > > Thanks, > -- > Bob Smither [email protected] > Circuit Concepts, Inc. 281-331-2744 > <smither.vcf> > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
