Multimeter Calibration and Voltage Referance


henasau@...
 

It would be interesting to know how members go about and keep in check accuracy of their workshop multimeters. I have 5 multimeters and each is giving slightly different results. It would be nice to calibrate them to a known voltage standard.


Of course I could pay the money and have them calibrated with the certificate but I am just wondering if there is an easy home made method to address this.



Henryk


Gary Robert Bosworth
 

Henryk:

I have seen certified voltage standards at some of the companies where I
worked. They usually had their voltage stamped on the outside to 5-digit
accuracy and traceable to the National Bureau of Standards. Perhaps you
could find one of these cells on eBay.

Gary
On Mar 27, 2015 3:13 AM, "henasau@... [TekScopes]" <
TekScopes@...> wrote:



It would be interesting to know how members go about and keep in check
accuracy of their workshop multimeters. I have 5 multimeters and each is
giving slightly different results. It would be nice to calibrate them to a
known voltage standard.


Of course I could pay the money and have them calibrated with the
certificate but I am just wondering if there is an easy home made method to
address this.



Henryk





[Non-text portions of this message have been removed]



[Non-text portions of this message have been removed]


stefan_trethan
 

I don't think a chemical voltage standard would be all that useful,
since the voltage does change as they age.
In a cal lab they would be periodically compared wih a superior
standard, and they'd keep track of that change.
So if you got an old dusty standard cell somewhere that change may not be known.
Also temperature and stuff has a big influence.

I think there are some reasonably accurate semiconductor references
for sale on Ebay and elsewhere, in the $40 range.
Those may well be your best option for checking or calibrating low end
multimeters.

ST



On Fri, Mar 27, 2015 at 12:01 PM, Gary Robert Bosworth
grbosworth@... [TekScopes] <TekScopes@...> wrote:
Henryk:

I have seen certified voltage standards at some of the companies where I
worked. They usually had their voltage stamped on the outside to 5-digit
accuracy and traceable to the National Bureau of Standards. Perhaps you
could find one of these cells on eBay.

Gary
On Mar 27, 2015 3:13 AM, "henasau@... [TekScopes]" <
TekScopes@...> wrote:


n4buq
 

I made a very simple board using one of the voltage reference chips. It's plenty accurate enough for an analog meter. A few high-precision resistive dividers are handy for other voltage ranges. Just a few dollars will get you some pretty good accuracy.

They ones on eBay have some calibration values printed on them and may be just a bit closer (same type of scheme, however) but are, as mentioned, in the $40 range.

Regards,
Barry - N4BUQ

----- Original Message -----
From: "Stefan Trethan stefan_trethan@... [TekScopes]" <TekScopes@...>
To: "TekScopes" <TekScopes@...>
Sent: Friday, March 27, 2015 6:49:17 AM
Subject: Re: [TekScopes] Multimeter Calibration and Voltage Referance

I don't think a chemical voltage standard would be all that useful,
since the voltage does change as they age.
In a cal lab they would be periodically compared wih a superior
standard, and they'd keep track of that change.
So if you got an old dusty standard cell somewhere that change may not be
known.
Also temperature and stuff has a big influence.

I think there are some reasonably accurate semiconductor references
for sale on Ebay and elsewhere, in the $40 range.
Those may well be your best option for checking or calibrating low end
multimeters.

ST



On Fri, Mar 27, 2015 at 12:01 PM, Gary Robert Bosworth
grbosworth@... [TekScopes] <TekScopes@...> wrote:
Henryk:

I have seen certified voltage standards at some of the companies where I
worked. They usually had their voltage stamped on the outside to 5-digit
accuracy and traceable to the National Bureau of Standards. Perhaps you
could find one of these cells on eBay.

Gary
On Mar 27, 2015 3:13 AM, "henasau@... [TekScopes]" <
TekScopes@...> wrote:


J. L. Trantham
 

It's curiosity like this that leads to 'addiction' to metrology. Be
careful.



Since you will never actually know the exact value of any 'standard', you
have to have something in your lab that you would 'trust'. For me, it's a
high quality DMM. Once that is professionally calibrated, you can use it to
'measure' your 'standards' for future reference and act as a 'transfer
standard' to calibrate your other meters.



The 'standards' can be a collection of various devices (resistors, voltage
standards, inductors, capacitors, frequency standards, etc.) or a
'multi-function' calibrator. I like the Fluke 5100B series that can be had
relatively cheaply from time to time but may well need some repair to get
them up and running. It provides DC and AC voltage, resistance and current.




It also depends on what 'standards' you need in order to properly calibrate
your meters.



It's my thought to have such a 'metrology section' in my lab but I have a
long way to go.



Good luck.



Joe



From: TekScopes@... [mailto:TekScopes@...]
Sent: Friday, March 27, 2015 5:13 AM
To: TekScopes@...
Subject: [Bulk] [TekScopes] Multimeter Calibration and Voltage Referance





It would be interesting to know how members go about and keep in check
accuracy of their workshop multimeters. I have 5 multimeters and each is
giving slightly different results. It would be nice to calibrate them to a
known voltage standard.


Of course I could pay the money and have them calibrated with the
certificate but I am just wondering if there is an easy home made method to
address this.



Henryk


n4buq
 

It all goes back to that old saying regarding a man with more than one watch never really knows what time it is...

I do the same as far as using a DMM. No, it isn't calibrated, but my DMMs pretty much agree with each other (and my voltage reference board) and I "trust" them for accuracy over their analog cousins.

For hobby use, that's good enough for me for most work.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "'J. L. Trantham' jltran@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Friday, March 27, 2015 8:13:37 AM
Subject: RE: [Bulk] [TekScopes] Multimeter Calibration and Voltage Referance

It's curiosity like this that leads to 'addiction' to metrology. Be
careful.



Since you will never actually know the exact value of any 'standard', you
have to have something in your lab that you would 'trust'. For me, it's a
high quality DMM. Once that is professionally calibrated, you can use it to
'measure' your 'standards' for future reference and act as a 'transfer
standard' to calibrate your other meters.



The 'standards' can be a collection of various devices (resistors, voltage
standards, inductors, capacitors, frequency standards, etc.) or a
'multi-function' calibrator. I like the Fluke 5100B series that can be had
relatively cheaply from time to time but may well need some repair to get
them up and running. It provides DC and AC voltage, resistance and current.




It also depends on what 'standards' you need in order to properly calibrate
your meters.



It's my thought to have such a 'metrology section' in my lab but I have a
long way to go.



Good luck.



Joe



From: TekScopes@... [mailto:TekScopes@...]
Sent: Friday, March 27, 2015 5:13 AM
To: TekScopes@...
Subject: [Bulk] [TekScopes] Multimeter Calibration and Voltage Referance





It would be interesting to know how members go about and keep in check
accuracy of their workshop multimeters. I have 5 multimeters and each is
giving slightly different results. It would be nice to calibrate them to a
known voltage standard.


Of course I could pay the money and have them calibrated with the
certificate but I am just wondering if there is an easy home made method to
address this.



Henryk














Dale H. Cook
 

At 06:12 AM 3/27/2015, Henryk wrote:

It would be interesting to know how members go about and keep in check accuracy of their workshop multimeters.
I own a vintage Hewlett-Packard VTVM calibration system (DC and 400 HZ), originally used by HP field techs. The last calibration run showed the output accuracy as 0.1% or better on all ranges.

Dale H. Cook, Roanoke/Lynchburg, VA
Osborne 1 / Kaypro 4-84 / Kaypro 1 / Amstrad PPC-640
http://plymouthcolony.net/starcity/radios/index.html


 

For voltage reference, I use a module I bought on eBay for $20 US.  Just search eBay for "voltage reference ad584" (without the quotes) and you will get many examples.  Some use the AD584L chip which is laser trimmed to +/- 5 mVolts which is good enough for most of us.  Mine came with a hand written "final value" paper that gave the values to 5 digits.
If you want a step up, check out Low Cost Precision Voltage References .  This seller offers several great references from simple DC voltage up to voltage (AC and DC), resistance, current, and frequency for $80 US.
 
|   |
|   | |   |   |   |   |   |
| Low Cost Precision Voltage ReferencesCheck out http://voltagestandard.com! voltagestandard.com low cost precision DC voltage references |
| |
| View on www.voltagestandard... | Preview by Yahoo |
| |
|   |

  From: "henasau@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Friday, March 27, 2015 5:12 AM
Subject: [TekScopes] Multimeter Calibration and Voltage Referance

  It would be interesting to know how members go about and keep in check accuracy of their workshop multimeters. I have 5 multimeters and each is giving slightly different results. It would be nice to calibrate them to a known voltage standard.


Of course I could pay the money and have them calibrated with the certificate but I am just wondering if there is an easy home made method to address this.



Henryk





[Non-text portions of this message have been removed]

#yiv3461629745 #yiv3461629745 -- #yiv3461629745ygrp-mkp {border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;}#yiv3461629745 #yiv3461629745ygrp-mkp hr {border:1px solid #d8d8d8;}#yiv3461629745 #yiv3461629745ygrp-mkp #yiv3461629745hd {color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;}#yiv3461629745 #yiv3461629745ygrp-mkp #yiv3461629745ads {margin-bottom:10px;}#yiv3461629745 #yiv3461629745ygrp-mkp .yiv3461629745ad {padding:0 0;}#yiv3461629745 #yiv3461629745ygrp-mkp .yiv3461629745ad p {margin:0;}#yiv3461629745 #yiv3461629745ygrp-mkp .yiv3461629745ad a {color:#0000ff;text-decoration:none;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ygrp-lc {font-family:Arial;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ygrp-lc #yiv3461629745hd {margin:10px 0px;font-weight:700;font-size:78%;line-height:122%;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ygrp-lc .yiv3461629745ad {margin-bottom:10px;padding:0 0;}#yiv3461629745 #yiv3461629745actions {font-family:Verdana;font-size:11px;padding:10px 0;}#yiv3461629745 #yiv3461629745activity {background-color:#e0ecee;float:left;font-family:Verdana;font-size:10px;padding:10px;}#yiv3461629745 #yiv3461629745activity span {font-weight:700;}#yiv3461629745 #yiv3461629745activity span:first-child {text-transform:uppercase;}#yiv3461629745 #yiv3461629745activity span a {color:#5085b6;text-decoration:none;}#yiv3461629745 #yiv3461629745activity span span {color:#ff7900;}#yiv3461629745 #yiv3461629745activity span .yiv3461629745underline {text-decoration:underline;}#yiv3461629745 .yiv3461629745attach {clear:both;display:table;font-family:Arial;font-size:12px;padding:10px 0;width:400px;}#yiv3461629745 .yiv3461629745attach div a {text-decoration:none;}#yiv3461629745 .yiv3461629745attach img {border:none;padding-right:5px;}#yiv3461629745 .yiv3461629745attach label {display:block;margin-bottom:5px;}#yiv3461629745 .yiv3461629745attach label a {text-decoration:none;}#yiv3461629745 blockquote {margin:0 0 0 4px;}#yiv3461629745 .yiv3461629745bold {font-family:Arial;font-size:13px;font-weight:700;}#yiv3461629745 .yiv3461629745bold a {text-decoration:none;}#yiv3461629745 dd.yiv3461629745last p a {font-family:Verdana;font-weight:700;}#yiv3461629745 dd.yiv3461629745last p span {margin-right:10px;font-family:Verdana;font-weight:700;}#yiv3461629745 dd.yiv3461629745last p span.yiv3461629745yshortcuts {margin-right:0;}#yiv3461629745 div.yiv3461629745attach-table div div a {text-decoration:none;}#yiv3461629745 div.yiv3461629745attach-table {width:400px;}#yiv3461629745 div.yiv3461629745file-title a, #yiv3461629745 div.yiv3461629745file-title a:active, #yiv3461629745 div.yiv3461629745file-title a:hover, #yiv3461629745 div.yiv3461629745file-title a:visited {text-decoration:none;}#yiv3461629745 div.yiv3461629745photo-title a, #yiv3461629745 div.yiv3461629745photo-title a:active, #yiv3461629745 div.yiv3461629745photo-title a:hover, #yiv3461629745 div.yiv3461629745photo-title a:visited {text-decoration:none;}#yiv3461629745 div#yiv3461629745ygrp-mlmsg #yiv3461629745ygrp-msg p a span.yiv3461629745yshortcuts {font-family:Verdana;font-size:10px;font-weight:normal;}#yiv3461629745 .yiv3461629745green {color:#628c2a;}#yiv3461629745 .yiv3461629745MsoNormal {margin:0 0 0 0;}#yiv3461629745 o {font-size:0;}#yiv3461629745 #yiv3461629745photos div {float:left;width:72px;}#yiv3461629745 #yiv3461629745photos div div {border:1px solid #666666;height:62px;overflow:hidden;width:62px;}#yiv3461629745 #yiv3461629745photos div label {color:#666666;font-size:10px;overflow:hidden;text-align:center;white-space:nowrap;width:64px;}#yiv3461629745 #yiv3461629745reco-category {font-size:77%;}#yiv3461629745 #yiv3461629745reco-desc {font-size:77%;}#yiv3461629745 .yiv3461629745replbq {margin:4px;}#yiv3461629745 #yiv3461629745ygrp-actbar div a:first-child {margin-right:2px;padding-right:5px;}#yiv3461629745 #yiv3461629745ygrp-mlmsg {font-size:13px;font-family:Arial, helvetica, clean, sans-serif;}#yiv3461629745 #yiv3461629745ygrp-mlmsg table {font-size:inherit;font:100%;}#yiv3461629745 #yiv3461629745ygrp-mlmsg select, #yiv3461629745 input, #yiv3461629745 textarea {font:99% Arial, Helvetica, clean, sans-serif;}#yiv3461629745 #yiv3461629745ygrp-mlmsg pre, #yiv3461629745 code {font:115% monospace;}#yiv3461629745 #yiv3461629745ygrp-mlmsg * {line-height:1.22em;}#yiv3461629745 #yiv3461629745ygrp-mlmsg #yiv3461629745logo {padding-bottom:10px;}#yiv3461629745 #yiv3461629745ygrp-msg p a {font-family:Verdana;}#yiv3461629745 #yiv3461629745ygrp-msg p#yiv3461629745attach-count span {color:#1E66AE;font-weight:700;}#yiv3461629745 #yiv3461629745ygrp-reco #yiv3461629745reco-head {color:#ff7900;font-weight:700;}#yiv3461629745 #yiv3461629745ygrp-reco {margin-bottom:20px;padding:0px;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ov li a {font-size:130%;text-decoration:none;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ov li {font-size:77%;list-style-type:square;padding:6px 0;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ov ul {margin:0;padding:0 0 0 8px;}#yiv3461629745 #yiv3461629745ygrp-text {font-family:Georgia;}#yiv3461629745 #yiv3461629745ygrp-text p {margin:0 0 1em 0;}#yiv3461629745 #yiv3461629745ygrp-text tt {font-size:120%;}#yiv3461629745 #yiv3461629745ygrp-vital ul li:last-child {border-right:none !important;}#yiv3461629745



[Non-text portions of this message have been removed]


Benedikt Dienst
 

To calibrate my whole equipment, I only drive to work!

regards
Ben

From: mailto:TekScopes@...
Sent: Friday, March 27, 2015 6:10 PM
To: TekScopes@...
Subject: Re: [TekScopes] Multimeter Calibration and Voltage Referance


For voltage reference, I use a module I bought on eBay for $20 US. Just search eBay for "voltage reference ad584" (without the quotes) and you will get many examples. Some use the AD584L chip which is laser trimmed to +/- 5 mVolts which is good enough for most of us. Mine came with a hand written "final value" paper that gave the values to 5 digits.
If you want a step up, check out Low Cost Precision Voltage References . This seller offers several great references from simple DC voltage up to voltage (AC and DC), resistance, current, and frequency for $80 US.

| |
| | | | | | | |
| Low Cost Precision Voltage ReferencesCheck out http://voltagestandard.com! voltagestandard.com low cost precision DC voltage references |
| |
| View on www.voltagestandard... | Preview by Yahoo |
| |
| |

From: "henasau@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Friday, March 27, 2015 5:12 AM
Subject: [TekScopes] Multimeter Calibration and Voltage Referance

It would be interesting to know how members go about and keep in check accuracy of their workshop multimeters. I have 5 multimeters and each is giving slightly different results. It would be nice to calibrate them to a known voltage standard.


Of course I could pay the money and have them calibrated with the certificate but I am just wondering if there is an easy home made method to address this.

Henryk




[Non-text portions of this message have been removed]

#yiv3461629745 #yiv3461629745 -- #yiv3461629745ygrp-mkp {border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;}#yiv3461629745 #yiv3461629745ygrp-mkp hr {border:1px solid #d8d8d8;}#yiv3461629745 #yiv3461629745ygrp-mkp #yiv3461629745hd {color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;}#yiv3461629745 #yiv3461629745ygrp-mkp #yiv3461629745ads {margin-bottom:10px;}#yiv3461629745 #yiv3461629745ygrp-mkp .yiv3461629745ad {padding:0 0;}#yiv3461629745 #yiv3461629745ygrp-mkp .yiv3461629745ad p {margin:0;}#yiv3461629745 #yiv3461629745ygrp-mkp .yiv3461629745ad a {color:#0000ff;text-decoration:none;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ygrp-lc {font-family:Arial;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ygrp-lc #yiv3461629745hd {margin:10px 0px;font-weight:700;font-size:78%;line-height:122%;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ygrp-lc .yiv3461629745ad {margin-bottom:10px;padding:0 0;}#yiv3461629745 #yiv3461629745actions {font-family:Verdana;font-size:11px;padding:10px 0;}#yiv3461629745 #yiv3461629745activity {background-color:#e0ecee;float:left;font-family:Verdana;font-size:10px;padding:10px;}#yiv3461629745 #yiv3461629745activity span {font-weight:700;}#yiv3461629745 #yiv3461629745activity span:first-child {text-transform:uppercase;}#yiv3461629745 #yiv3461629745activity span a {color:#5085b6;text-decoration:none;}#yiv3461629745 #yiv3461629745activity span span {color:#ff7900;}#yiv3461629745 #yiv3461629745activity span .yiv3461629745underline {text-decoration:underline;}#yiv3461629745 .yiv3461629745attach {clear:both;display:table;font-family:Arial;font-size:12px;padding:10px 0;width:400px;}#yiv3461629745 .yiv3461629745attach div a {text-decoration:none;}#yiv3461629745 .yiv3461629745attach img {border:none;padding-right:5px;}#yiv3461629745 .yiv3461629745attach label {display:block;margin-bottom:5px;}#yiv3461629745 .yiv3461629745attach label a {text-decoration:none;}#yiv3461629745 blockquote {margin:0 0 0 4px;}#yiv3461629745 .yiv3461629745bold {font-family:Arial;font-size:13px;font-weight:700;}#yiv3461629745 .yiv3461629745bold a {text-decoration:none;}#yiv3461629745 dd.yiv3461629745last p a {font-family:Verdana;font-weight:700;}#yiv3461629745 dd.yiv3461629745last p span {margin-right:10px;font-family:Verdana;font-weight:700;}#yiv3461629745 dd.yiv3461629745last p span.yiv3461629745yshortcuts {margin-right:0;}#yiv3461629745 div.yiv3461629745attach-table div div a {text-decoration:none;}#yiv3461629745 div.yiv3461629745attach-table {width:400px;}#yiv3461629745 div.yiv3461629745file-title a, #yiv3461629745 div.yiv3461629745file-title a:active, #yiv3461629745 div.yiv3461629745file-title a:hover, #yiv3461629745 div.yiv3461629745file-title a:visited {text-decoration:none;}#yiv3461629745 div.yiv3461629745photo-title a, #yiv3461629745 div.yiv3461629745photo-title a:active, #yiv3461629745 div.yiv3461629745photo-title a:hover, #yiv3461629745 div.yiv3461629745photo-title a:visited {text-decoration:none;}#yiv3461629745 div#yiv3461629745ygrp-mlmsg #yiv3461629745ygrp-msg p a span.yiv3461629745yshortcuts {font-family:Verdana;font-size:10px;font-weight:normal;}#yiv3461629745 .yiv3461629745green {color:#628c2a;}#yiv3461629745 .yiv3461629745MsoNormal {margin:0 0 0 0;}#yiv3461629745 o {font-size:0;}#yiv3461629745 #yiv3461629745photos div {float:left;width:72px;}#yiv3461629745 #yiv3461629745photos div div {border:1px solid #666666;height:62px;overflow:hidden;width:62px;}#yiv3461629745 #yiv3461629745photos div label {color:#666666;font-size:10px;overflow:hidden;text-align:center;white-space:nowrap;width:64px;}#yiv3461629745 #yiv3461629745reco-category {font-size:77%;}#yiv3461629745 #yiv3461629745reco-desc {font-size:77%;}#yiv3461629745 .yiv3461629745replbq {margin:4px;}#yiv3461629745 #yiv3461629745ygrp-actbar div a:first-child {margin-right:2px;padding-right:5px;}#yiv3461629745 #yiv3461629745ygrp-mlmsg {font-size:13px;font-family:Arial, helvetica, clean, sans-serif;}#yiv3461629745 #yiv3461629745ygrp-mlmsg table {font-size:inherit;font:100%;}#yiv3461629745 #yiv3461629745ygrp-mlmsg select, #yiv3461629745 input, #yiv3461629745 textarea {font:99% Arial, Helvetica, clean, sans-serif;}#yiv3461629745 #yiv3461629745ygrp-mlmsg pre, #yiv3461629745 code {font:115% monospace;}#yiv3461629745 #yiv3461629745ygrp-mlmsg * {line-height:1.22em;}#yiv3461629745 #yiv3461629745ygrp-mlmsg #yiv3461629745logo {padding-bottom:10px;}#yiv3461629745 #yiv3461629745ygrp-msg p a {font-family:Verdana;}#yiv3461629745 #yiv3461629745ygrp-msg p#yiv3461629745attach-count span {color:#1E66AE;font-weight:700;}#yiv3461629745 #yiv3461629745ygrp-reco #yiv3461629745reco-head {color:#ff7900;font-weight:700;}#yiv3461629745 #yiv3461629745ygrp-reco {margin-bottom:20px;padding:0px;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ov li a {font-size:130%;text-decoration:none;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ov li {font-size:77%;list-style-type:square;padding:6px 0;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ov ul {margin:0;padding:0 0 0 8px;}#yiv3461629745 #yiv3461629745ygrp-text {font-family:Georgia;}#yiv3461629745 #yiv3461629745ygrp-text p {margin:0 0 1em 0;}#yiv3461629745 #yiv3461629745ygrp-text tt {font-size:120%;}#yiv3461629745 #yiv3461629745ygrp-vital ul li:last-child {border-right:none !important;}#yiv3461629745

[Non-text portions of this message have been removed]





[Non-text portions of this message have been removed]


Bob Albert
 

I have a gold standard voltmeter, HP 3456A that takes care of everything. I actually have three very accurate voltmeters but the HP is the one on my bench that I use for a master reference.  It's good to better than .01% for most voltages and resistance.  It also measures AC volts.  For current I simply use a measured low value wire wound resistor and calculate the current.  For passive components I use the GR 1658 which is good to maybe 0.1% or better.  For frequency I have a nice counter with OCXO that I occasionally check with WWV.
These instruments are available used (and uncalibrated) for very reasonable prices.  Even uncalibrated they are far better than the everyday type of VOM, including the inexpensive digital ones.
Bob

On Friday, March 27, 2015 10:27 AM, "'Bene's Mails' bene.dienst@... [TekScopes]" <TekScopes@...> wrote:


  To calibrate my whole equipment, I only drive to work!

regards
Ben

From: mailto:TekScopes@...
Sent: Friday, March 27, 2015 6:10 PM
To: TekScopes@...
Subject: Re: [TekScopes] Multimeter Calibration and Voltage Referance

For voltage reference, I use a module I bought on eBay for $20 US. Just search eBay for "voltage reference ad584" (without the quotes) and you will get many examples. Some use the AD584L chip which is laser trimmed to +/- 5 mVolts which is good enough for most of us. Mine came with a hand written "final value" paper that gave the values to 5 digits.
If you want a step up, check out Low Cost Precision Voltage References . This seller offers several great references from simple DC voltage up to voltage (AC and DC), resistance, current, and frequency for $80 US.

| |
| | | | | | | |
| Low Cost Precision Voltage ReferencesCheck out http://voltagestandard.com! voltagestandard.com low cost precision DC voltage references |
| |
| View on www.voltagestandard... | Preview by Yahoo |
| |
| |

From: "henasau@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Friday, March 27, 2015 5:12 AM
Subject: [TekScopes] Multimeter Calibration and Voltage Referance

It would be interesting to know how members go about and keep in check accuracy of their workshop multimeters. I have 5 multimeters and each is giving slightly different results. It would be nice to calibrate them to a known voltage standard.

Of course I could pay the money and have them calibrated with the certificate but I am just wondering if there is an easy home made method to address this.

Henryk



#yiv3461629745 #yiv3461629745 -- #yiv3461629745ygrp-mkp {border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;}#yiv3461629745 #yiv3461629745ygrp-mkp hr {border:1px solid #d8d8d8;}#yiv3461629745 #yiv3461629745ygrp-mkp #yiv3461629745hd {color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;}#yiv3461629745 #yiv3461629745ygrp-mkp #yiv3461629745ads {margin-bottom:10px;}#yiv3461629745 #yiv3461629745ygrp-mkp .yiv3461629745ad {padding:0 0;}#yiv3461629745 #yiv3461629745ygrp-mkp .yiv3461629745ad p {margin:0;}#yiv3461629745 #yiv3461629745ygrp-mkp .yiv3461629745ad a {color:#0000ff;text-decoration:none;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ygrp-lc {font-family:Arial;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ygrp-lc #yiv3461629745hd {margin:10px 0px;font-weight:700;font-size:78%;line-height:122%;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ygrp-lc .yiv3461629745ad {margin-bottom:10px;padding:0 0;}#yiv3461629745 #yiv3461629745actions {font-family:Verdana;font-size:11px;padding:10px 0;}#yiv3461629745 #yiv3461629745activity {background-color:#e0ecee;float:left;font-family:Verdana;font-size:10px;padding:10px;}#yiv3461629745 #yiv3461629745activity span {font-weight:700;}#yiv3461629745 #yiv3461629745activity span:first-child {text-transform:uppercase;}#yiv3461629745 #yiv3461629745activity span a {color:#5085b6;text-decoration:none;}#yiv3461629745 #yiv3461629745activity span span {color:#ff7900;}#yiv3461629745 #yiv3461629745activity span .yiv3461629745underline {text-decoration:underline;}#yiv3461629745 .yiv3461629745attach {clear:both;display:table;font-family:Arial;font-size:12px;padding:10px 0;width:400px;}#yiv3461629745 .yiv3461629745attach div a {text-decoration:none;}#yiv3461629745 .yiv3461629745attach img {border:none;padding-right:5px;}#yiv3461629745 .yiv3461629745attach label {display:block;margin-bottom:5px;}#yiv3461629745 .yiv3461629745attach label a {text-decoration:none;}#yiv3461629745 blockquote {margin:0 0 0 4px;}#yiv3461629745 .yiv3461629745bold {font-family:Arial;font-size:13px;font-weight:700;}#yiv3461629745 .yiv3461629745bold a {text-decoration:none;}#yiv3461629745 dd.yiv3461629745last p a {font-family:Verdana;font-weight:700;}#yiv3461629745 dd.yiv3461629745last p span {margin-right:10px;font-family:Verdana;font-weight:700;}#yiv3461629745 dd.yiv3461629745last p span.yiv3461629745yshortcuts {margin-right:0;}#yiv3461629745 div.yiv3461629745attach-table div div a {text-decoration:none;}#yiv3461629745 div.yiv3461629745attach-table {width:400px;}#yiv3461629745 div.yiv3461629745file-title a, #yiv3461629745 div.yiv3461629745file-title a:active, #yiv3461629745 div.yiv3461629745file-title a:hover, #yiv3461629745 div.yiv3461629745file-title a:visited {text-decoration:none;}#yiv3461629745 div.yiv3461629745photo-title a, #yiv3461629745 div.yiv3461629745photo-title a:active, #yiv3461629745 div.yiv3461629745photo-title a:hover, #yiv3461629745 div.yiv3461629745photo-title a:visited {text-decoration:none;}#yiv3461629745 div#yiv3461629745ygrp-mlmsg #yiv3461629745ygrp-msg p a span.yiv3461629745yshortcuts {font-family:Verdana;font-size:10px;font-weight:normal;}#yiv3461629745 .yiv3461629745green {color:#628c2a;}#yiv3461629745 .yiv3461629745MsoNormal {margin:0 0 0 0;}#yiv3461629745 o {font-size:0;}#yiv3461629745 #yiv3461629745photos div {float:left;width:72px;}#yiv3461629745 #yiv3461629745photos div div {border:1px solid #666666;height:62px;overflow:hidden;width:62px;}#yiv3461629745 #yiv3461629745photos div label {color:#666666;font-size:10px;overflow:hidden;text-align:center;white-space:nowrap;width:64px;}#yiv3461629745 #yiv3461629745reco-category {font-size:77%;}#yiv3461629745 #yiv3461629745reco-desc {font-size:77%;}#yiv3461629745 .yiv3461629745replbq {margin:4px;}#yiv3461629745 #yiv3461629745ygrp-actbar div a:first-child {margin-right:2px;padding-right:5px;}#yiv3461629745 #yiv3461629745ygrp-mlmsg {font-size:13px;font-family:Arial, helvetica, clean, sans-serif;}#yiv3461629745 #yiv3461629745ygrp-mlmsg table {font-size:inherit;font:100%;}#yiv3461629745 #yiv3461629745ygrp-mlmsg select, #yiv3461629745 input, #yiv3461629745 textarea {font:99% Arial, Helvetica, clean, sans-serif;}#yiv3461629745 #yiv3461629745ygrp-mlmsg pre, #yiv3461629745 code {font:115% monospace;}#yiv3461629745 #yiv3461629745ygrp-mlmsg * {line-height:1.22em;}#yiv3461629745 #yiv3461629745ygrp-mlmsg #yiv3461629745logo {padding-bottom:10px;}#yiv3461629745 #yiv3461629745ygrp-msg p a {font-family:Verdana;}#yiv3461629745 #yiv3461629745ygrp-msg p#yiv3461629745attach-count span {color:#1E66AE;font-weight:700;}#yiv3461629745 #yiv3461629745ygrp-reco #yiv3461629745reco-head {color:#ff7900;font-weight:700;}#yiv3461629745 #yiv3461629745ygrp-reco {margin-bottom:20px;padding:0px;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ov li a {font-size:130%;text-decoration:none;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ov li {font-size:77%;list-style-type:square;padding:6px 0;}#yiv3461629745 #yiv3461629745ygrp-sponsor #yiv3461629745ov ul {margin:0;padding:0 0 0 8px;}#yiv3461629745 #yiv3461629745ygrp-text {font-family:Georgia;}#yiv3461629745 #yiv3461629745ygrp-text p {margin:0 0 1em 0;}#yiv3461629745 #yiv3461629745ygrp-text tt {font-size:120%;}#yiv3461629745 #yiv3461629745ygrp-vital ul li:last-child {border-right:none !important;}#yiv3461629745

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

#yiv9356035518 #yiv9356035518 -- #yiv9356035518ygrp-mkp {border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;}#yiv9356035518 #yiv9356035518ygrp-mkp hr {border:1px solid #d8d8d8;}#yiv9356035518 #yiv9356035518ygrp-mkp #yiv9356035518hd {color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;}#yiv9356035518 #yiv9356035518ygrp-mkp #yiv9356035518ads {margin-bottom:10px;}#yiv9356035518 #yiv9356035518ygrp-mkp .yiv9356035518ad {padding:0 0;}#yiv9356035518 #yiv9356035518ygrp-mkp .yiv9356035518ad p {margin:0;}#yiv9356035518 #yiv9356035518ygrp-mkp .yiv9356035518ad a {color:#0000ff;text-decoration:none;}#yiv9356035518 #yiv9356035518ygrp-sponsor #yiv9356035518ygrp-lc {font-family:Arial;}#yiv9356035518 #yiv9356035518ygrp-sponsor #yiv9356035518ygrp-lc #yiv9356035518hd {margin:10px 0px;font-weight:700;font-size:78%;line-height:122%;}#yiv9356035518 #yiv9356035518ygrp-sponsor #yiv9356035518ygrp-lc .yiv9356035518ad {margin-bottom:10px;padding:0 0;}#yiv9356035518 #yiv9356035518actions {font-family:Verdana;font-size:11px;padding:10px 0;}#yiv9356035518 #yiv9356035518activity {background-color:#e0ecee;float:left;font-family:Verdana;font-size:10px;padding:10px;}#yiv9356035518 #yiv9356035518activity span {font-weight:700;}#yiv9356035518 #yiv9356035518activity span:first-child {text-transform:uppercase;}#yiv9356035518 #yiv9356035518activity span a {color:#5085b6;text-decoration:none;}#yiv9356035518 #yiv9356035518activity span span {color:#ff7900;}#yiv9356035518 #yiv9356035518activity span .yiv9356035518underline {text-decoration:underline;}#yiv9356035518 .yiv9356035518attach {clear:both;display:table;font-family:Arial;font-size:12px;padding:10px 0;width:400px;}#yiv9356035518 .yiv9356035518attach div a {text-decoration:none;}#yiv9356035518 .yiv9356035518attach img {border:none;padding-right:5px;}#yiv9356035518 .yiv9356035518attach label {display:block;margin-bottom:5px;}#yiv9356035518 .yiv9356035518attach label a {text-decoration:none;}#yiv9356035518 blockquote {margin:0 0 0 4px;}#yiv9356035518 .yiv9356035518bold {font-family:Arial;font-size:13px;font-weight:700;}#yiv9356035518 .yiv9356035518bold a {text-decoration:none;}#yiv9356035518 dd.yiv9356035518last p a {font-family:Verdana;font-weight:700;}#yiv9356035518 dd.yiv9356035518last p span {margin-right:10px;font-family:Verdana;font-weight:700;}#yiv9356035518 dd.yiv9356035518last p span.yiv9356035518yshortcuts {margin-right:0;}#yiv9356035518 div.yiv9356035518attach-table div div a {text-decoration:none;}#yiv9356035518 div.yiv9356035518attach-table {width:400px;}#yiv9356035518 div.yiv9356035518file-title a, #yiv9356035518 div.yiv9356035518file-title a:active, #yiv9356035518 div.yiv9356035518file-title a:hover, #yiv9356035518 div.yiv9356035518file-title a:visited {text-decoration:none;}#yiv9356035518 div.yiv9356035518photo-title a, #yiv9356035518 div.yiv9356035518photo-title a:active, #yiv9356035518 div.yiv9356035518photo-title a:hover, #yiv9356035518 div.yiv9356035518photo-title a:visited {text-decoration:none;}#yiv9356035518 div#yiv9356035518ygrp-mlmsg #yiv9356035518ygrp-msg p a span.yiv9356035518yshortcuts {font-family:Verdana;font-size:10px;font-weight:normal;}#yiv9356035518 .yiv9356035518green {color:#628c2a;}#yiv9356035518 .yiv9356035518MsoNormal {margin:0 0 0 0;}#yiv9356035518 o {font-size:0;}#yiv9356035518 #yiv9356035518photos div {float:left;width:72px;}#yiv9356035518 #yiv9356035518photos div div {border:1px solid #666666;height:62px;overflow:hidden;width:62px;}#yiv9356035518 #yiv9356035518photos div label {color:#666666;font-size:10px;overflow:hidden;text-align:center;white-space:nowrap;width:64px;}#yiv9356035518 #yiv9356035518reco-category {font-size:77%;}#yiv9356035518 #yiv9356035518reco-desc {font-size:77%;}#yiv9356035518 .yiv9356035518replbq {margin:4px;}#yiv9356035518 #yiv9356035518ygrp-actbar div a:first-child {margin-right:2px;padding-right:5px;}#yiv9356035518 #yiv9356035518ygrp-mlmsg {font-size:13px;font-family:Arial, helvetica, clean, sans-serif;}#yiv9356035518 #yiv9356035518ygrp-mlmsg table {font-size:inherit;font:100%;}#yiv9356035518 #yiv9356035518ygrp-mlmsg select, #yiv9356035518 input, #yiv9356035518 textarea {font:99% Arial, Helvetica, clean, sans-serif;}#yiv9356035518 #yiv9356035518ygrp-mlmsg pre, #yiv9356035518 code {font:115% monospace;}#yiv9356035518 #yiv9356035518ygrp-mlmsg * {line-height:1.22em;}#yiv9356035518 #yiv9356035518ygrp-mlmsg #yiv9356035518logo {padding-bottom:10px;}#yiv9356035518 #yiv9356035518ygrp-msg p a {font-family:Verdana;}#yiv9356035518 #yiv9356035518ygrp-msg p#yiv9356035518attach-count span {color:#1E66AE;font-weight:700;}#yiv9356035518 #yiv9356035518ygrp-reco #yiv9356035518reco-head {color:#ff7900;font-weight:700;}#yiv9356035518 #yiv9356035518ygrp-reco {margin-bottom:20px;padding:0px;}#yiv9356035518 #yiv9356035518ygrp-sponsor #yiv9356035518ov li a {font-size:130%;text-decoration:none;}#yiv9356035518 #yiv9356035518ygrp-sponsor #yiv9356035518ov li {font-size:77%;list-style-type:square;padding:6px 0;}#yiv9356035518 #yiv9356035518ygrp-sponsor #yiv9356035518ov ul {margin:0;padding:0 0 0 8px;}#yiv9356035518 #yiv9356035518ygrp-text {font-family:Georgia;}#yiv9356035518 #yiv9356035518ygrp-text p {margin:0 0 1em 0;}#yiv9356035518 #yiv9356035518ygrp-text tt {font-size:120%;}#yiv9356035518 #yiv9356035518ygrp-vital ul li:last-child {border-right:none !important;}#yiv9356035518



[Non-text portions of this message have been removed]


Sergey Kubushyn
 

On Fri, 27 Mar 2015, Stefan Trethan stefan_trethan@... [TekScopes] wrote:

Chemical Voltage Standards are er.., Standards. They do NOT require
calibration against same standards because they are based on fundamental
constants so they are primary standards on their own right. They last for at
least tens of years and they were what NIST used as primary standards in not
so distant past until better standards were developed. Unfortunately those
are too big and bothersome to keep in one's garage but good old Weston cells
are more than adequate to calibrate ANY regular instrument including
top-of-the-cream HP 3458A and Datron/Wavetek 1281.

The devil is, as usual in the details. First of all you need SATURATED
Weston cells. _ALL_ those you see on Ebay and wherever else are UNSATURATED
ones so they have their EMF falling with a time so they need periodic checks
against real standards to find their actual EMF. This is the price you pay
for transportability and lower thermal coefficient. These days there is
absolutely no sense for those -- LTZ1000A beats them heads down and way more
convenient. However LTZ1000A voltage source require calibration against
known standard. It is pretty stable when calibrated (after several years of
aging of course) so it holds its voltage very good but ABSOLUTE value is
unknown until calibrated. Even LM399AH is better than old unsaturated Weston
cell and those are available from e.g. DigiKey at less than $10 in single
quantities (LM399AH-ND part number.)

SATURATE Weston cells are standards theirselves. They do NOT need
calibration. Their EMF is based on fundamental constants so they ALWAYS give
the exact (to some degree) ABSOLUTE known voltage that can be used as a
standard to calibrate all other sources against.

However it comes with a cost. First of all they have high temperature
coefficient so you have to keep them in an oil bath with very stable and
precise temperature. Temperature should be either kept at exact spot (that
does not require a very linear and precise thermal sensor but the entire
bath must be calibrated to that spot temperature) or its temperature must be
known with high accuracy if it is not at that spot so necessary correction
can be calculated (that is totally different task from keeping it at exact
spot.)

Then, saturated cells are NOT transportable. They can not be shipped so
there is only one way to get those -- make them in place. It is not terribly
complex or outrageously expensive job but it requires some equipment, tools,
materials, and skills that are usually not available. But if one can do some
relatively basic glassblowing, has adequate chemical lab and chemistry
knowledge it is not a very big deal. All materials can be purchased online,
most of them even not requiring additional purification.

I don't think a chemical voltage standard would be all that useful,
since the voltage does change as they age.
In a cal lab they would be periodically compared wih a superior
standard, and they'd keep track of that change.
So if you got an old dusty standard cell somewhere that change may not be known.
Also temperature and stuff has a big influence.

I think there are some reasonably accurate semiconductor references
for sale on Ebay and elsewhere, in the $40 range.
Those may well be your best option for checking or calibrating low end
multimeters.

ST



On Fri, Mar 27, 2015 at 12:01 PM, Gary Robert Bosworth
grbosworth@... [TekScopes] <TekScopes@...> wrote:
Henryk:

I have seen certified voltage standards at some of the companies where I
worked. They usually had their voltage stamped on the outside to 5-digit
accuracy and traceable to the National Bureau of Standards. Perhaps you
could find one of these cells on eBay.

Gary
On Mar 27, 2015 3:13 AM, "henasau@... [TekScopes]" <
TekScopes@...> wrote:

------------------------------------
Posted by: Stefan Trethan <stefan_trethan@...>
------------------------------------


------------------------------------

Yahoo Groups Links


---
******************************************************************
* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *
******************************************************************


Sergey Kubushyn
 

On Fri, 27 Mar 2015, 'J. L. Trantham' jltran@... [TekScopes] wrote:

It's curiosity like this that leads to 'addiction' to metrology. Be
careful.
Yep, it is EXTREMELY contagious and very severe, no cure known :)

---
******************************************************************
* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *
******************************************************************


stefan_trethan
 

I think I did okay, considering that I don't have the volt nuts ;-)

Thanks for the clarification.

ST

On Fri, Mar 27, 2015 at 6:46 PM, Sergey Kubushyn ksi@...
[TekScopes] <TekScopes@...> wrote:
On Fri, 27 Mar 2015, Stefan Trethan stefan_trethan@... [TekScopes] wrote:

Chemical Voltage Standards are er.., Standards. They do NOT require
calibration against same standards because they are based on fundamental
constants so they are primary standards on their own right. They last for at
least tens of years and they were what NIST used as primary standards in not
so distant past until better standards were developed. Unfortunately those
are too big and bothersome to keep in one's garage but good old Weston cells
are more than adequate to calibrate ANY regular instrument including
top-of-the-cream HP 3458A and Datron/Wavetek 1281.

The devil is, as usual in the details. First of all you need SATURATED
Weston cells. _ALL_ those you see on Ebay and wherever else are UNSATURATED
ones so they have their EMF falling with a time so they need periodic checks
against real standards to find their actual EMF. This is the price you pay
for transportability and lower thermal coefficient. These days there is
absolutely no sense for those -- LTZ1000A beats them heads down and way more
convenient. However LTZ1000A voltage source require calibration against
known standard. It is pretty stable when calibrated (after several years of
aging of course) so it holds its voltage very good but ABSOLUTE value is
unknown until calibrated. Even LM399AH is better than old unsaturated Weston
cell and those are available from e.g. DigiKey at less than $10 in single
quantities (LM399AH-ND part number.)

SATURATE Weston cells are standards theirselves. They do NOT need
calibration. Their EMF is based on fundamental constants so they ALWAYS give
the exact (to some degree) ABSOLUTE known voltage that can be used as a
standard to calibrate all other sources against.

However it comes with a cost. First of all they have high temperature
coefficient so you have to keep them in an oil bath with very stable and
precise temperature. Temperature should be either kept at exact spot (that
does not require a very linear and precise thermal sensor but the entire
bath must be calibrated to that spot temperature) or its temperature must be
known with high accuracy if it is not at that spot so necessary correction
can be calculated (that is totally different task from keeping it at exact
spot.)

Then, saturated cells are NOT transportable. They can not be shipped so
there is only one way to get those -- make them in place. It is not terribly
complex or outrageously expensive job but it requires some equipment, tools,
materials, and skills that are usually not available. But if one can do some
relatively basic glassblowing, has adequate chemical lab and chemistry
knowledge it is not a very big deal. All materials can be purchased online,
most of them even not requiring additional purification.

I don't think a chemical voltage standard would be all that useful,
since the voltage does change as they age.
In a cal lab they would be periodically compared wih a superior
standard, and they'd keep track of that change.
So if you got an old dusty standard cell somewhere that change may not be known.
Also temperature and stuff has a big influence.

I think there are some reasonably accurate semiconductor references
for sale on Ebay and elsewhere, in the $40 range.
Those may well be your best option for checking or calibrating low end
multimeters.

ST



On Fri, Mar 27, 2015 at 12:01 PM, Gary Robert Bosworth
grbosworth@... [TekScopes] <TekScopes@...> wrote:
Henryk:

I have seen certified voltage standards at some of the companies where I
worked. They usually had their voltage stamped on the outside to 5-digit
accuracy and traceable to the National Bureau of Standards. Perhaps you
could find one of these cells on eBay.

Gary
On Mar 27, 2015 3:13 AM, "henasau@... [TekScopes]" <
TekScopes@...> wrote:

------------------------------------
Posted by: Stefan Trethan <stefan_trethan@...>
------------------------------------


------------------------------------

Yahoo Groups Links


---
******************************************************************
* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *
******************************************************************


------------------------------------
Posted by: Sergey Kubushyn <ksi@...>
------------------------------------


------------------------------------

Yahoo Groups Links



Steve D
 

I have the DMMCheck Plus from http://www.voltagestandard.com/DMMCheck_Plus.html http://www.voltagestandard.com/DMMCheck_Plus.html. It is a relatively inexpensive "standard" that includes precision AC and DC standards, 2 frequency standards, a precision current source and several precision resistors. It comes with a calibration slip that tells you exactly what your particular standards are.

I recently purchased a new Fluke DMM and a BK Precision bench DMM. According to the DMMCheck Plus, the Fluke was dead on. The BK was outside their stated accuracy. To make a long story short, BK finally agreed to "check the calibration" on the meter if I would pay to send it back. I did and they found it to be out exactly to the extent the DMMCheck Plus said it was. It really irritated me to have to pay to ship an instrument back to the vendor to get them to make it like it was supposed to be in the first place but anyway, both my BK and my Fluke are now DEAD on. I use the DMMCheck Plus to check my scopes as well and it has proven to be VERY valuable in giving me the confidence that my measurements are right.

Voltagestandards is a great company to work with as well. They will recalibrate the standard free for (I think) the first two years and after that, it's very reasonable to have them calibrate it.

Hope this helps someone,

Steve


Manfred Mornhinweg
 

Henryk,

For many years I just did sanity checks with my meters: I had four multimeters of different types and qualities, including a clamp meter. If three agreed within their accuracy ratings, and one disagreed, that was the one that needed to be checked over. Usually when there is that much error that one can spot it that way, something went outright wrong, and it's not just a calibration issue. Typical problems are high contact resistance, slightly conductive dirt, or a resistor that took an overload and changed value. So the meter needs repair rather than recalibration - and often after the repair it won't need recalibration, at least for hobby use!

Two years ago I bought my fifth multimeter. This one is a high end unit, in terms of functions and accuracy (but not in price). One of my intentions when buying it was having that one thing I can trust. And I had the intentions of recalibrating my old meters to this new, high accuracy one. But I found that only my analog meter required a slight touch-up. All the digital meters were still well within their accuracy specs - and the oldest of them is 27 years old!

To check resistance ranges, high accuracy resistors are available at reasonable cost.

And a comment, now that we are talking meters: Despite having bought that fancy high accuracy meter, I still use mostly my oldest DMM, despite its much more modest specs and its shabby appearance! The reason: It uses two AA batteries, and they last ten years, at a rate of two hours a day. It consumes only some microamperes. The new meter instead uses a 9V battery, and eats it in just about 25 hours! Even low spec modern DMMs use much more battery current than old ones. I wonder why. I don't enjoy buying, replacing and throwing away batteries all the time.

Manfred


========================
Visit my hobby homepage!
http://ludens.cl
========================


stefan_trethan
 

BK gear seems to be all Chinese imports now.
I was considering to buy a load from them for work, hoping for better service.
If they are like that I may as well buy the Chinese version and save a
few hundred.


ST


On Fri, Mar 27, 2015 at 11:07 PM, n4bos@... [TekScopes]

I recently purchased a new Fluke DMM and a BK Precision bench DMM. According to the DMMCheck Plus, the Fluke was dead on. The BK was outside their stated accuracy. To make a long story short, BK finally agreed to "check the calibration" on the meter if I would pay to send it back. I did and they found it to be out exactly to the extent the DMMCheck Plus said it was. It really irritated me to have to pay to ship an instrument back to the vendor to get them to make it like it was supposed to be in the first place but anyway, both my BK and my Fluke are now DEAD on.


Manfred Mornhinweg
 

Stefan,

If they are like that I may as well buy the Chinese version and save a
few hundred.
That's exactly what I did! I bought the Uni-T UT71E, direct from China. Some people say this is the "Chinese Fluke". I have heard that the same factory actually makes current Fluke meters - no idea if that's true, though. The meter works pretty well, has far better accuracy ratings than most current meters, and has some rather rare and very useful functions, such as measuring real and reactive power. But it eats batteries. And its auto-zeroing is overzealous: When measuring very small values, it will sometimes stubbornly lock into displaying 0.0000!

I planned to use this as my main DMM, replacing my much more modest and very old Taiwanese Yu Fong YF-1220, but the Unit-T's high battery drain made me change that decision.

At work (while I still worked!) I used mostly Fluke DMMs, such as the 75, 77, and mainly the 87. That one also ate batteries, but at work I didn't care that much about it...

My analog multimeter is a Philips ST-505, which has 50 kiloohm per volt, better than most. It serves me very well, as there are some measurements that are far better made with analog meters. In addition I have a crappy Mastech clamp meter, but at least it does DC, which most clamp meters don't; and an even crappier minimalist Cen-Tech that I got for free. That's the one I use when I need to check whether a circuit has 12V or 12kV in it... Not much to lose! ;-)

Manfred

========================
Visit my hobby homepage!
http://ludens.cl
========================


Peter Gottlieb
 

About 25 years ago I worked at a place which bought a lot of Fluke meters. One of the engineers made a deal with the sales rep where we could buy them personally for even a better price than the company paid, and that was one of my few ever hobbyist buys of a new piece of test equipment (so much surplus out there!). I was not disappointed and use that meter daily to this day. I recently checked its calibration against a newly calibrated HP 34401A and it is still dead on. I've worked at many places since and always buy Fluke meters for my department. Why mess around?

Peter

On 3/28/2015 9:57 AM, Manfred Mornhinweg manfred@... [TekScopes] wrote:
Stefan,

If they are like that I may as well buy the Chinese version and save a
few hundred.
That's exactly what I did! I bought the Uni-T UT71E, direct from China. Some
people say this is the "Chinese Fluke". I have heard that the same factory
actually makes current Fluke meters - no idea if that's true, though. The meter
works pretty well, has far better accuracy ratings than most current meters, and
has some rather rare and very useful functions, such as measuring real and
reactive power. But it eats batteries. And its auto-zeroing is overzealous: When
measuring very small values, it will sometimes stubbornly lock into displaying
0.0000!

I planned to use this as my main DMM, replacing my much more modest and very old
Taiwanese Yu Fong YF-1220, but the Unit-T's high battery drain made me change
that decision.

At work (while I still worked!) I used mostly Fluke DMMs, such as the 75, 77,
and mainly the 87. That one also ate batteries, but at work I didn't care that
much about it...

My analog multimeter is a Philips ST-505, which has 50 kiloohm per volt, better
than most. It serves me very well, as there are some measurements that are far
better made with analog meters. In addition I have a crappy Mastech clamp meter,
but at least it does DC, which most clamp meters don't; and an even crappier
minimalist Cen-Tech that I got for free. That's the one I use when I need to
check whether a circuit has 12V or 12kV in it... Not much to lose! ;-)

Manfred

========================
Visit my hobby homepage!
http://ludens.cl
========================


------------------------------------

------------------------------------


------------------------------------

Yahoo Groups Links




stefan_trethan
 

Manfred,

The Fluke 87 draws about half operating current in "auto power off" mode.
So it really eats batteries if one forgets.

However I always grab a Fluke, not sure why.
I have many handheld meters (a couple dozen), some clearly better such
as Norma (which, made in Austria, are of course far superior to any US
made meter ;-)), but I still always grab the Fluke.

A Fluke may not do much, but it just works, and will take most abuse
(including mechanical) without stopping to work.

The older Fluke 87 at work start to go wonky around the switch now (if
you press on it weird things happen), but they have seen so much use I
can accept that.

I'm happy to pay a little extra for a better quality product, but NOT
FOR A BRAND NAME LABEL ON A CHEAP IMPORT, like the Keithley 2110 for
example.

ST



On Sat, Mar 28, 2015 at 2:57 PM, Manfred Mornhinweg manfred@...
[TekScopes] <TekScopes@...> wrote:

Stefan,

If they are like that I may as well buy the Chinese version and save a
few hundred.
That's exactly what I did! I bought the Uni-T UT71E, direct from China. Some
people say this is the "Chinese Fluke". I have heard that the same factory
actually makes current Fluke meters - no idea if that's true, though. The meter
works pretty well, has far better accuracy ratings than most current meters, and
has some rather rare and very useful functions, such as measuring real and
reactive power. But it eats batteries. And its auto-zeroing is overzealous: When
measuring very small values, it will sometimes stubbornly lock into displaying
0.0000!

I planned to use this as my main DMM, replacing my much more modest and very old
Taiwanese Yu Fong YF-1220, but the Unit-T's high battery drain made me change
that decision.

At work (while I still worked!) I used mostly Fluke DMMs, such as the 75, 77,
and mainly the 87. That one also ate batteries, but at work I didn't care that
much about it...

My analog multimeter is a Philips ST-505, which has 50 kiloohm per volt, better
than most. It serves me very well, as there are some measurements that are far
better made with analog meters. In addition I have a crappy Mastech clamp meter,
but at least it does DC, which most clamp meters don't; and an even crappier
minimalist Cen-Tech that I got for free. That's the one I use when I need to
check whether a circuit has 12V or 12kV in it... Not much to lose! ;-)

Manfred

========================
Visit my hobby homepage!
http://ludens.cl
========================


------------------------------------

------------------------------------


------------------------------------

Yahoo Groups Links



Gary Robert Bosworth
 

I have had several Fluke DVMs that I have been very pleased with.

I owned a Fluke dual temperature measuring hand-held that was intermittent.
I had to throw it in the trash. Did anyone else suffer a similar
phenomenon?

Gary
On Mar 28, 2015 9:45 AM, "Stefan Trethan stefan_trethan@...
[TekScopes]" <TekScopes@...> wrote:



Manfred,

The Fluke 87 draws about half operating current in "auto power off" mode.
So it really eats batteries if one forgets.

However I always grab a Fluke, not sure why.
I have many handheld meters (a couple dozen), some clearly better such
as Norma (which, made in Austria, are of course far superior to any US
made meter ;-)), but I still always grab the Fluke.

A Fluke may not do much, but it just works, and will take most abuse
(including mechanical) without stopping to work.

The older Fluke 87 at work start to go wonky around the switch now (if
you press on it weird things happen), but they have seen so much use I
can accept that.

I'm happy to pay a little extra for a better quality product, but NOT
FOR A BRAND NAME LABEL ON A CHEAP IMPORT, like the Keithley 2110 for
example.

ST

On Sat, Mar 28, 2015 at 2:57 PM, Manfred Mornhinweg manfred@...
[TekScopes] <TekScopes@...> wrote:

Stefan,

If they are like that I may as well buy the Chinese version and save a
few hundred.
That's exactly what I did! I bought the Uni-T UT71E, direct from China.
Some
people say this is the "Chinese Fluke". I have heard that the same
factory
actually makes current Fluke meters - no idea if that's true, though.
The meter
works pretty well, has far better accuracy ratings than most current
meters, and
has some rather rare and very useful functions, such as measuring real
and
reactive power. But it eats batteries. And its auto-zeroing is
overzealous: When
measuring very small values, it will sometimes stubbornly lock into
displaying
0.0000!

I planned to use this as my main DMM, replacing my much more modest and
very old
Taiwanese Yu Fong YF-1220, but the Unit-T's high battery drain made me
change
that decision.

At work (while I still worked!) I used mostly Fluke DMMs, such as the
75, 77,
and mainly the 87. That one also ate batteries, but at work I didn't
care that
much about it...

My analog multimeter is a Philips ST-505, which has 50 kiloohm per volt,
better
than most. It serves me very well, as there are some measurements that
are far
better made with analog meters. In addition I have a crappy Mastech
clamp meter,
but at least it does DC, which most clamp meters don't; and an even
crappier
minimalist Cen-Tech that I got for free. That's the one I use when I
need to
check whether a circuit has 12V or 12kV in it... Not much to lose! ;-)

Manfred

========================
Visit my hobby homepage!
http://ludens.cl
========================


------------------------------------

------------------------------------


------------------------------------

Yahoo Groups Links



[Non-text portions of this message have been removed]