Handheld Precision Digital Voltage Source - IanJohnston.com - Page 1
Forum section: electronics / general

author: IanJ
author_rank: Unknown
timestamp: January 08, 2016, 03:48:07 pm
content: Hi all,Finally!!!.......I've built up a first batch of my Handheld Precision Digital Voltage Source's and are available to purchase via my online shop.http://www.ianjohnston.com/index.php/onlineshopA big thanks to Dave for giving me the push I needed to go into production after featuring one of my early prototypes in his Mailbag Monday a couple months ago.I've made quite a few changes since the mailbag and have addressed a few niggles Dave commented on, i.e.- Better stability- Less noise on output- Better quality banana sockets- More intuitive user interface- Internal sense line to banana's allowing heavier loads without compromising output voltage accuracy- Coax ditched in favour of heavy gauge wire- MAX6350 Vref ditched in favour of an LM399AH = much better stability and tempco.Below is a photo of the production unit, any questions please ask via the contact form on my site:-http://www.ianjohnston.com/index.php/contactFUNCTIONS & FEATURES:-- 50mV to 10Vdc user adjustable output (4d.p’s, 5d.p’s extended, i.e. 10’s of uV’s).- Voltage setting or ramp up/down controls via the 12 button numeric keypad.- Soft power switch.- Based on the industry standard LM399AH voltage reference.- No potentiometers inside or outside.- 18bit DAC with an accuracy/stability down in the tens of uV’s (using a PLC filter of 1.0 or higher).- Battery voltage monitor, including low voltage warning and auto-shutdown.- Output voltage monitor including overload / short circuit protection.- 3” Graphics LCD (128x64 pixels).- Atmel 328P micro-controller (uses Arduino bootloader).- Precision chopper op-amp on final output with extra stability achieved using low tempco resistors.- Re-calibration by the user possible via keypad/LCD and saved to flash rom.- Battery powered.- Battery reverse polarity protection.- Quality Hammond 1599 case.- Quality aluminium anodized & engraved front panel.- Quality 4mm banana sockets.- Single PCB integrating the analog & digital electronics, LCD, keypad & battery terminals.- Printed manual including factory calibration/settings record supplied. Unique serial number.Ian.www.ianjohnston.com

author: Vgkid
author_rank: Super Contributor
timestamp: January 08, 2016, 09:44:08 pm
content: You have done a really nice job on it.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 09, 2016, 12:14:13 am
content: Well outside of my hobbyist budget but a DAMN nice looking device!

author: HKJ
author_rank: Super Contributor
timestamp: January 13, 2016, 07:47:31 am
content: Nice job, but I would have liked an encoder in addition to the keyboard.And why the big margin (100mV) before it warns about output "out of tolerance"?

author: babysitter
author_rank: Frequent Contributor
timestamp: January 13, 2016, 08:43:49 am
content: Looks good - do you want some reviews?What I miss is a programmable "true" zero volt output.

author: HKJ
author_rank: Super Contributor
timestamp: January 15, 2016, 07:38:40 pm
content: Fast shipping, I received mine today.The calibration looks good, my two best DMM's show x.0000yy (in a few cases z.9999yy) when checking the different full voltage steps. This check was done after more than one hour with power and ACAL on the DMM's/you unit (DMM's: Keysight 34470A and Keithley DMM7510). I will probably not bother doing my own calibration.This was exactly what I hoped for, thank you.But it would have been nice if you mailed the calibration certificate, now I will have to scan it (Paper manuals disappears rather fast).

author: maukka
author_rank: Unknown
timestamp: April 21, 2017, 01:11:11 pm
content: The new version seems to be available for order now!http://www.ianjohnston.com/index.php/onlineshop/handheld-precision-digital-voltage-source-v2-detail

author: jasonbrent
author_rank: Regular Contributor
timestamp: January 17, 2018, 05:14:11 am
content: @IanJ - Are you expecting a new batch soonish?-j