Fluke 732A DC Voltage Standard & low cost DIY attempt

Flex or FR4, get your advanced PCBs from https://www.pcbway.com/setinvite.aspx...
5% off Brymen & Siglent w/ coupon 'marcoreps5' https://www.welectron.com/
Miniware LCR tweezers https://www.banggood.com/custlink/vDv...
Thermal imager https://www.banggood.com/custlink/Kvm...
Stereo microscope https://www.banggood.com/custlink/KmG...
Exclusive videos sometimes on   / marcoreps  

IanScottJohnston transformer anatomy    • No.061 - HP 3457A DMM Repair - Rewind...  
Massively simplified 732A Falstad sim https://tinyurl.com/yzcvd2pn
LTZ1000A Falstad sim https://tinyurl.com/yj8tvqjo
Has cool stuff other than feedthroughs   / gigabecquerel  
Alternative hermetic feedthrough pins: Tusonix / CTS 4300
Mu metal cans https://de.rs-online.com/web/p/audio-...
0.2 ppm/°C VSMP resistors https://de.rs-online.com/web/c/passiv...
R-Core transformer https://s.click.aliexpress.com/e/_Aq6SMY
Wavetek 7000 EEVblog forum https://www.eevblog.com/forum/metrolo...
Schroff RatiopacPRO AIR https://schroff.nvent.com/en-de/produ...
LTZ1000 tests with various 'above' resistors https://snapshot.raintank.io/dashboar...
A few days in the life of 732A https://snapshot.raintank.io/dashboar...
Fluke 5700A cal check logs https://github.com/marcoreps/5700A/tr...
LTZmu stats w/ imbalanced batteries https://snapshot.raintank.io/dashboar...
LTZmu project WIP https://github.com/marcoreps/LTZmu


00:00 Intro
02:01 Fluke 732A
02:55 732A battery
04:35 732A guarding
06:00 732A pre-regulator
07:32 732A ref assembly
09:11 732A thermals
10:42 732A 'fixes'
12:06 732A heater circuit
12:42 732A ref circuit
14:31 LTZmu 10V standard
15:33 LTZmu-metal cans
16:08 LTZmu SMD resistors
17:00 LTZmu flex PCBs
18:49 LTZmu assembly
20:23 LTZmu concepts
23:20 LTZmu surroundings
26:46 LTZmu circuit
27:48 Wavetek 7000
32:16 732A results
34:07 LTZmu no results yet