Tag Archives: DMM

Used-Line Has Chosen its First Dealer of the Month: Congratulations MATsolutions!

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The Used-Line Test Community Has Chosen!

MATsolutions is the Dealer of the Month.

DoftheM

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Used-Line’s Test Community voted for you because of your customer service, honesty, and reliability!

Since 1992, MATsolutions has delivered the assurance our clients need when acquiring, maintaining, and managing high quality reconditioned test and measurement equipment. MATsolutions purchases, sells, rents, and leases equipment from over 50 manufacturers and specializes in Agilent (Keysight), Tektronix, Rohde & Schwarz, Anritsu, and Fluke products. We also provide expert test equipment calibration and repair services in our state-of-the-art ISO 17025 Accredited Laboratory. MATsolutions can provide a repair solution to maintain older test platforms beyond the OEM end of service period.

MATsolutions Products

on Used-Line.com

Fluke 5720A

Fluke 5720A

Agilent/Keysight N9010A

Agilent/Keysight N9010A

Agilent/HP E8257D

Agilent/HP E8257D

More Products from MATsolutions

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What to Consider when Purchasing a Digital Multimeter

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The Digital Multimeter (DMM) is the most fundamental test and measurement instrument in the electronic technician kit or engineer’s lab bench. It provides a number of functions, the most common being resistance, voltage and current. Secondary functions can include temperature, induced current, low frequency measurement, and other routine tests needed to troubleshoot circuits.

DMM types

Many technicians use more than one digital multimeter, as they tend to be designed to suit a particular purpose in various environments. A DMM used in a clean room or laboratory is totally unsuitable for use in an outdoor environment or under harsh or hazardous conditions. In practical use, the DMM may need to be operated while wearing gloves during an ice storm, or may need to be handheld, extremely compact, and lightweight for portability. They can be rack mounted in a semi-permanent installation to be in close proximity to equipment that needs to be constantly monitored.

Here is an example of a DMM that can operate in temperatures below -40°C: The Agilent U1273AX.

U1273AX Specifications and FeaturesLearn more about the various features and specifications for the U1273AX.

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DMM accuracy standards

Some DMMs are functional and practical, even without routine regular calibration certification. When the tolerance of a resistor may be 10% or 20%, a DMM accurate within 3% is generally sufficient. In the days of analog D’Arsonval meters, parallax distortion and the vagaries of electromechanical movement could result in erroneous readings near 2 to 3%. DMMS are far more stable and immune to misinterpretation of the readout.

 DMM longevity

DMMs have a relatively high attrition rate. This is the result of multiple meters required by each technician in the field and not so much a failure of an instrument. DMMs are designed to be used hundreds of times a day, both in laboratory and field conditions. Field equipment is often subject to abuse from impact of a dropped instrument to total immersion in water and similar environmental hazards. Laboratory equipment needs to be replaced as technologies advance and evolve.

DMM features

DMMs are basically the same instrument, regardless of the make or model. What distinguishes one from another are cosmetic appearance and the user interactive interfaces. Each of these differences are highlighted as features. Not every meter can have every feature; it is up to the technician to know which configuration on a DMM is optimal for any given situation.

DMM advanced or enhanced features

Some typical enhancements include dual displays, RS-232, USB or IEEE computer interfaces, audible alarms or tone feedback, which enables the technician to keep his eyes on the device under test rather than on the meter. High-priced options include very tight measurement tolerances. Some enhancements can include backlit LCD displays, as opposed to LED displays. Induced current “clamp meters” and similar exterior measurement accessories are usually optional, but may be included as a part of a package. Some features include hold and store min/max readings, auto-ranging or auto-sensing circuitry and similar hands-free operation. If multiple and various readings are necessary, these features can offer a vast improvement over manual ranging and repeated button-pushing to change DMM settings.

Here is a DMM with a USB host port on the front panel: The Tektronix DMM4040.

DMM4040 Specifications and FeaturesLearn more about the various features and specifications for the DMM4040.

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 Advantages of used DMMs

Of course, this is where Used-Line comes into the story. Leasing companies, larger companies employing scores of technicians, or smaller small- to medium-sized businesses seeking to stay within tight budgets can be well-served by considering procurement of used and re-certified, discontinued models or factory-refurbished DMMs. This is a cost-effective solution that will serve the company now and into the future. All technicians have particular makes and models of test instruments that they have high-confidence with using every day. In field applications, many techs prefer Fluke and Simpson meters for their ruggedness, durability and useful features without resorting to gimmicks or unnecessary bells-and-whistles. Given that some DMMs can cost over $10,000, depending on the degree of precision and accuracy required, buying used or as-new discontinued instruments can make or break a budget.

 Selecting the right DMM

Choose the best quality instrument that meets your need. With higher-priced test equipment it is a wise idea to lease an instrument to ensure its suitability to the task. Realize that equipment turn-over for many of the top leasing companies is due to deprecating features or advancing technology. Leasing companies frequently sell their equipment to used-line.com clients in sufficient quantities to make offering them at steep discounts possible, with no sacrifice to name-brand quality, dependability and service.

We can’t exit this blog post without showing a Fluke. If you’re looking for 365-day stability, have a look at the Fluke 8508A reference multimeter.

8508A Specifications and FeaturesLearn more about the various features and specifications for the 8508A.

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It’s All in the Tool

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TRAVELLING BACK IN TIME

So there I was in front of the kitchen sink, scrubbing this pot that had at least eight years of grime stuck to it, having realized that I don’t want to keep serving Chicken Cacciatore left over from January 2013 to my family. Nor that delicious pot roast in wine sauce that I concocted in March 2012. I mean, both beef and wine do age well, but we’re talking health hazards here – not epicurean tastes.
So, sighing with muscle fatigue, regretting that I had stopped popping in to the neighborhood gym park some time ago, and realizing that the only iron I was pumping these days was beneath the enamel of the above-mentioned pot, I opted for a coffee break, using my left hand to pour (my right arm having ceased to function normally after its scrubbing aerobics), and decided to rest for a few minutes and ponder the tackling of this task.

coffeeCoffee always inspires! I remembered! The green baize scrubby thingy works wonders! Well, not exactly baize – more like a rough green plasticy sheet that feels gentler than sandpaper but works in the same way. After a thorough search for a piece of the green wonder (the coffee gave me the energy to do this), I found some of this treasure in the drawer at the bottom of a kitchen closet that only opens if all the other doors in the room are closed (Don’t even ask!). A few minutes inside my pot, after taking another rest to recover from the drawer/closet battle, and I could view my own reflection inside my suddenly-like-new pot!

DON’T LET THE EQUIPMENT BEAT YOU! YOU CAN DO THIS!

This ultimately successful experience reminded me that winning battles with equipment is all in the tool! It threw me back to my technician days at Bull HN Information Systems. H = Honeywell, and N = NEC. If you are too young to have heard of Groupe Bull (pronounced Bee-yool in France, home of the company’s corporate headquarters) in their Honeywell days, here’s a link to a little history about Honeywell and it’s relationship with Bull.

Don’t Let The Equipment Beat You! You Can Do This! Click To Tweet

A BRAND NEW & PROUD ELECTRONICS ENGINEERING TECHNICIAN

Proud to have graduated as an electronics engineering technician from Seneca College, Toronto, I arrived at my first job in 1991 – at Bull’s Component Repair shop in Scarborough, Ontario, eager to try out my new troubleshooting skills with a DMM and scope. My analytical skills knew no bounds. Really, all you need to know to succeed in this work are a few logic gate specs and some sort of expectations about what should be showing up on those pins: 5 V, maybe 3.3 V, 0 V. Some interesting waveforms on the screen. Right?

Wrong!

INFORMATIVE REPAIR REQUISITION SLIPS

So, first things first. Read the complaint written on the Repair Requisition slip. These can be very informative.
Like this one:
“Dead”.

A DEAD DUMB TERMINAL?!

That’s quite useful information. Usually it produces the avoidance response. Avoid powering up the instrument. Avoid calling up the customer to enquire, “So what’s actually wrong with the instrument?” Why not just avoid trying to repair it?

Not an option.

LET’S CLIMB INSIDE A MONOCHROME HONEYWELL DPS

Okay, then, let’s take a look INSIDE! My job was to repair monochrome monitors and Honeywell DPS “dumb” terminals. The terminals weren’t really dumb – but after a while, the technician (yours truly) got to feel like not such a bright spark.

In order to view the inside of the instrument, you need to open it up. How I struggled to open those boxes. On my first day on the job, I was presented with a set of tools including a power screwdriver, all shiny and red.

It had a forward/reverse button and I had two bits for it, a Phillips and a flathead. As soon as I saw it, I thought, “This is it!” This tool will take me anywhere I need to go.
As it turned out – not everywhere.

Well, after ruining the threads of almost every screw on the terminal, I bashfully, in a rather subdued voice, approached my co-workers for advice. “Help me, help me, help!”, she cried. After ensuring that there were no hunters chasing after little rabbits, (Scarborough, Ontario not really being a cottage-in-the-woods kinda place) three technicians called out in unison: “It’s All in The Tool”!

I dropped my powered screwdriver like a hot cake, and trying to be brave, dared to ask, “What tool?!”

Screwdriver in toolbox

THE POWER OF PHILLIPS SCREWDRIVERS

And out they came – the powerful, yes, but not powered – the wonderful Phillips screwdrivers in all shapes, sizes, and lengths. Why did I not have one of these in my default tool set? Because they all came from Dad’s toolbox in his shed in the backyard. Note that ISO 9002 came later – we were still basking in the days of unrestricted shop conditions. They went on to explain that the power screwdrivers are fine for many tasks but not for those stubborn screws that have become embedded in plastic after years of heating. It’s guaranteed that they will want to remain right where they are. But, wait, there’s more.

THEY DID NOT TEACH ME ABOUT TORQUE IN SCHOOL

It’s not only in the tool, my new instructors cried – it’s also in the torque. Torque? And then my new-found instructors taught me how to use the tool. Choose the correct size screwdriver, position the tool correctly in the screw, apply pressure. and only then, turn. Fortunately, those were the days preceding my need to take coffee breaks each time I applied a little torque, else I would probably have been responsible for breaking some sort of Union law relating to multiple coffee breaks.

THANK YOU, BULL HN COMPONENT REPAIR IN SCARBOROUGH, ONTARIO

After that, opening equipment became a breeze. I couldn’t wait to pass on my new-found knowledge to the new wet-behind-the-ears recruits, who, like me, thought they knew it all. Now, so many years later, I would like to thank my co-workers in Bull HN Component Repair for their patience, excellent skills, and teaching abilities. I really appreciated all your assistance. Thank you!


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