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Author Topic: Do you own an outdated multimeter within 2019?  (Read 66 times)

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Online Kiriakos GR

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Do you own an outdated multimeter within 2019?
« on: May 07, 2019, 09:56:08 PM »
Vast majority of people not working professionally in electronics repairs they are unable to imagine what makes a multimeter this now called as Outdated.

Additionally many people now starting their engagement with electronics (learning), they are also unaware or deliberately closing their eyes at accepting that even passive electronics parts they are now made with better technology.

Within 2019 a multimeter this must be also a component tester this be capable to test electronic components of our times starting for a single resistor.

Basic carbon resistor this is now grandfather of later produced Through-Hole Metal Film Resistors and of recently produced thick film resistors.
Today both Through-Hole and SMD (surface mount resistor) they follow more tight tolerances than the ancient standard of resistance tolerances at 10% or 5%.

Use of thick film technology in resistors, these helped resistors to be made at lower resistance tolerances 1.0% and down to 0.1% or lower.

Today SMD (surface mount resistors) these now replaced at about 80% the use of full size carbon resistors.
Industry leaders in production of electronic circuits, they also set new standards, they requested from resistors industry this to deliver small size and lower tolerances’, both requirements’ assisting in production of higher precision electronics.

Neither fresh produced cement resistors escaped from enjoying fresh upgraded tight tolerances close to 0.5%.

Precision made passive electronics these now raising the need for more precisely made multimeter to be used for electronics components inspection and repair.
Vast majority of surface mount resistors they are now made at 1% tolerance and even lower if it is requested.

Therefore higher resistor tolerances’ of 5% or 10% these are now mostly a toy for hobbyists and or for use at not-critical applications.
Not critical applications this translates today to Low-End electronics that no one will care to send for repair because of their low price.

Outdated multimeter this is now the one which does not have necessary precision tolerance (error %) so this to measure accurately down to 1% tolerance resistor.
But beware that this conclusion it is to characterize and separate appropriate multimeter to use from inappropriate ones.

My engagement all these years with electrical metrology this teaches me of safe rule to follow, this is no other than using measuring equipment five times better than DUT (device under test) or passive component under test.

First conclusion this is us following industry as this running ahead, we have no other choice than making buying decisions according to our electrical or electronics applications that we selects engaging with.
Benchtop 6 ½ multimeter accuracy at measuring resistors was down to 0.05% (12 months CAL) twelve years ago, in this decade several handheld meters they also have respectable accuracy and tight error tolerances for measuring newest resistors production (finest made one).

Recently I did engage with true high precision resistors at 0.005% tolerance.
And despite the fact that ITTSB blog still has finest HH multimeter samples in it collection, no one was qualifying measuring such high precision resistors at high resolution.
Only a dedicated high precision resistance-meter this retailed at 3000 Euro was capable to deliver measurements that you can believe and trust.
Now that is two years later than my first high precision resistor tests, I did use as comparison point also a precision DMM, this retailed at 1600 ~ 1800 Euro price point.
In my surprise this DMM came close speaking of measured values at most of it measuring ranges, this manage to deliver -0.06% deviation from measurement delivered by dedicated resistance meter which this including self-calibration every 4 minutes.
This DMM is not calibrated for six years, therefore such tiny drift of -0.06% this is not the issue.
But DMM measurement repeatability was not on par with dedicated high precision resistance-meter when this was challenged at seven digits resolution, instead first five digits was correct in most of tests. 

Best way seeing or thinking of a multimeter today, this is seeing it as to be a ladder, if you choose cheapest sorter ladder? Soon enough you will feel helpless when working with resistor tolerances at 1%.

What If you choose medium height low cost ladder?  Measurement stability and repeatability both are sacrificed and only emotionally you will have the confidence that your meter can do the trick when in reality this digital device it is unable to handle what is supposed that it will.

What If you choose medium height but high quality ladder?  Well this is the ideal for most applications by excluding the ones which probably pay more in the food chain of electrical applications.         
What If you choose among highest ones and highest in quality ladder?  By following this option, you are now gained compatibility with 99% of applications hidden in industrial sites.
Production of potato chips all having identical shape and flavor this counts it success at monitoring temperature by the use of platinum temperature sensors, that is a resistor (sensor) changing it value according temperature, 1 °C temperature change will cause a 0.384 ohm change in resistance.
In case of half degree Celsius this is 0.192 ohm change in resistance.
And also ten steps in a single Celsius this represents 0.038 ohm change in resistance.
The chart used for Celsius to Resistance value conversion, this is using 5 digits resolution at 10 Ohms range.
Pt 100 high accuracy sensor this is available at about 0.06% accuracy specifications, a five times better in specification multimeter this is what it is required. 

If there is a final conclusion this is just one, if you ever come close to get a job this demanding from you having a high quality ladder in your tool box, and this is missing, you will simply never get the job, or if you do? You will never deliver upon customer expectations and your reputation if any this will be destroyed.

Electrical work this is you cooperating with science, you are not in position to set your own rules, but to follow best practices available for your own benefit. 
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