** These are now all SOLD -- thanks! **I have home made LTZ1000 references, these have battery backup, and have been running continuously since late 2019.
I posted some details about the slightly earlier version here:
https://www.eevblog.com/forum/metrology/ultra-precision-reference-ltz1000/msg2785940/#msg2785940But the summary is:
- LTZ1000 reference based on the PCB designed by Dr Frank (very sightly modified)
- LiPo battery backup, originally lasted about 3 days without power, haven't tested them recently.
- Audible alarm for mains on/off, and when batteries get low (can be switched off)
- Flashing LED gives indication of charge/discharge state
- 7V and 10V outputs
If needed I can provide the schematics and PCB design for the power supply, and front and rear panels, but I can't find the code for the Atmel controller on the front (this is relatively simple, mostly just ADC operations to check power and charge state, and then controlling the LED and beeper.)
I have three of them, at 10.000068V, 10.000100V, and 9.999920V, there is an adjustment pot in there for fine adjustment, but if I remember correctly the last one wouldn't go above that value (I think my maths was slightly out with the main resistors), but I have left them all as they are for the last three years so they are well aged.
Any interest? I'm thinking £100 each, or perhaps £250 for all three? (plus shipping). PM if interested.
Lee.