Chinese voltage reference module - Page 1
Forum section: electronics / testgear

author: bigsky
author_rank: Regular Contributor
timestamp: October 23, 2014, 02:41:33 pm
content: I just got one of the chinese voltage references on ebay. It cost GBP 13 and took under three weeks to arrive.Here are some pics of it with my 87V, which dates from just after the GSM RFI fix so about three years old.I don't know what more there is to say, especially given the accuracy of the meter in hi-res mode.

author: Fungus
author_rank: Super Contributor
timestamp: October 23, 2014, 03:10:03 pm
content: Quote from: bigsky on October 23, 2014, 02:41:33 pmWhich voltage reference? This one...?http://www.ebay.com/itm/181112567159Quote from: bigsky on October 23, 2014, 02:41:33 pmThe chip it's based on:http://www.analog.com/static/imported-files/data_sheets/AD584.pdfWhere to get one:http://www.ebay.com/itm/360853364819

author: bigsky
author_rank: Regular Contributor
timestamp: October 23, 2014, 03:23:52 pm
content: Yes, that one. I thought people would know it's built around the AD584. My 87V hasn't been calibrated or adjusted since it left the factory.

author: Fungus
author_rank: Super Contributor
timestamp: October 23, 2014, 03:25:54 pm
content: It's an interesting topic...How do you guys test your meters (if at all)?I made a little tester a couple of weeks ago that does ohms, volts and amps. It has:10 kOhm and 1 kOhm - 0.01%5V and 2.048V - 0.05%10 mA and 100 uA - 0.5%Here's a quick snapshot with my crappy 'phone. Note 8-pin SOIC adapter boards(I need some taller standoffs so I can put another board underneath to hold the 9V battery and make it pretty...)

author: Fungus
author_rank: Super Contributor
timestamp: October 23, 2014, 03:36:15 pm
content: Quote from: bigsky on October 23, 2014, 03:23:52 pmI don't think they drift much, if at all. They're designed not to.The only people who need regular calibration are people who have to cover their asses when lawyers appear.

author: bigsky
author_rank: Regular Contributor
timestamp: October 23, 2014, 03:37:03 pm
content: Quote from: Fungus on October 23, 2014, 03:25:54 pmIf you're not careful it will end up looking like:Seehttp://www.voltagestandard.com/DMMCheck.htmlAnd on herehttps://www.eevblog.com/forum/chat/incoming-stuff-voltage-reference/

author: Fungus
author_rank: Super Contributor
timestamp: October 23, 2014, 03:42:18 pm
content: Quote from: bigsky on October 23, 2014, 03:37:03 pmCheap-ass gadget. My little metal hoops are gold plated!And instead of getting some decent resistors they just got some 1% resistors, measured them, then wrote the readings on a piece of paper. Tsk.

author: Fungus
author_rank: Super Contributor
timestamp: October 23, 2014, 06:41:49 pm
content: Quote from: butterfly on October 23, 2014, 05:52:22 pmI haven't actually looked at mine on a 'scope but that's why I put those two capacitors right behind the voltage references. I figured that between the battery power source and those capacitors there wasn't much else I could do.(Plus: My old Fluke measured exactly 5.00V and 2.048V on the very first attempt so I decided I was good to go...)

author: metasequoia
author_rank: Newbie
timestamp: October 25, 2014, 02:53:29 pm
content: I would like to make a correction to the statement regarding the 100K, 10K, and 1K resistors used on the DMMCheck made by voltagestandard.com- they are 0.1%, 25ppm/C parts. If you look closely at the photograph you can see that the color of the tolerance band is violet, indicating 0.1% tolerance.