The Trainer #72 - Mastering Your Digital Multimeter (DMM or DVOM)

Рет қаралды 91,864

Күн бұрын

What were the first tools you ever purchased? Of course, there was the selection of the basic hand tools and power tools, right? A basic tool box to keep it all in was also part of that initial investment, I’ll bet. But what about diagnostic equipment? Was a high end scan tool on your list? What about a scope? Odds are, neither were during the early part of your career.
I am willing to bet, though, that a Digital Multimeter was. It’s a tool that is as vital to a technician as a hammer is to a carpenter. We use it to measure the resistance of electrical components, voltage potential in a battery, and some of us even use it to measure current flow in a working circuit. Good uses, all, but there is so much more that the DMM can perform and so many ways it can be used to solve a variety of diagnostic dilemmas.
In this edition of The Trainer, we’ll take a look at the features included with most DMMs you may or may not be familiar with, how to perform some of the more standard tests with the meter, and then share some testing techniques you may never have considered using your meter for.
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Due to factors beyond the control of Motor Age, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. Motor Age magazine (UBM Americas - Automotive Group) assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Motor Age recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of Motor Age, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not Motor Age magazine or its corporate parent, UBM Americas.

Пікірлер: 63

@mikeburdi3464 2 ай бұрын

Hey Pete, thanks again for the great info and content that you and the Motor Age team are always putting out! 👍🏼 I have been in the trade for 30+ years and have gotten a bit of a reputation in my area as an electrical diagnostics specialist, my customers say that, not me. However, even though most of us know everything you just spoke about, it never hurts to hear it again, and again, and.... you get the idea. Nobody is perfect or knows everything, and even if you do it doesn't hurt to refresh your memory or sometimes you may suddenly see something from a different perspective. We are never to old to learn! Cheers and respect to you and to all of the mechanics out there, professional or diy backyard let's stick together! 👌🏼👍🏼

@tonychandler8908 5 жыл бұрын

I have got so much useful information from this program I have been a tech for 43years Pete you are the best for me to learn from I work on heave duty trucks been with the same dealership for 31years in Tuscaloosa Alabama

@MotorAgeMagazine 5 жыл бұрын

Glad you're enjoying it!

@justinsorci5998 Жыл бұрын

It’s also important when checking parasitic electrical draw to make sure the hood switch is rigged to be in the closed position (taped down, or temporarily zip tied down, etc.), and all the doors are closed. Otherwise, with the hood up the electrical system won’t go into sleep mode. Also, after testing, be sure to remove the tape or zip tie from the hood switch. I put a Post-It note on the vehicle’s dash instrumentation as a reminder of anything that can easily be overlooked…..when working on cars, it’s easy to set distracted by interruptions, phone calls, customers, etc.

@MotorAgeMagazine Жыл бұрын

Thanks for those great comments!

@misterrightfix4129 6 жыл бұрын

Very good information! Thank you so much for taking the time.

@fredigonzalez4372 3 жыл бұрын

Hello Mr. Pete Thank you for sharing with us all your knowledge and Wisdom... I personally have learned a lot from you, Im your No. 1 fan See you next time

@ceesteven 5 жыл бұрын

Good job! Thank you for the info.

@kellyr9388 6 жыл бұрын

Good refresher Pete

@malcolmyoung7866 6 жыл бұрын

Great video, thanks for sharing..

@konstantinusstoyanov9749 4 жыл бұрын

Thank you for sharing, learned something new

@samr.m.7709 6 жыл бұрын

Great video Pete, thank you sharing. Measuring the voltage drop across the fuse to find a parasitic draw is a fantastic method for diagnosing the draw.

@wyattoneable 6 жыл бұрын

I appreciate the information.

@stevewheatley243 3 жыл бұрын

Very informative. I'll get more use from my multimeter now.

@kennethmckee4223 6 жыл бұрын

great video

@richardjones3112 4 жыл бұрын

Been using Flukes for years in heavy industry (steelworks).Brilliant meters and virtually indestructible.

@HikerBiker 5 жыл бұрын

Like the test for checking starting/charging, first time I've heard of that one. I'll try it on my 2018 Transit as I've been having some starting issues I don't think are normal but the local dealer told me it is. They wouldn't even take the time to check it out.

@garylee1544 Жыл бұрын

Long before the Automotive Electrical systems became so Advanced, FLUKE was the Industry Standard for Industrial Instrumentation. Before that it was a Simpson 260 DVOM. Pete, what did they use in the Navy? Thanks for So Many Great Video's!!

@nickayivor8432 2 жыл бұрын

KNOWLEDGEABLE Sir Pete Meier Motor Age Thanks 👍 From Nick Ayivor from London England UK 🇬🇧

@mike-yp1uk 2 жыл бұрын

Ghost voltage is usually 60 hertz from your florescent lights. It shows up better on the scope.

@paultavres9830 5 жыл бұрын

I also have a fluke 88 Number one tip fluke says is Always start a test from meter off position That way you are more likely to set your meter to the correct position Sample if your going to test for bad alternator diode after checking alternator voltage going from DC volts to meter off then AC volts or if your going to check current Go to meter off then amps This method is the fluke recommend system in their self pace module along with many other tips One accessory i got with it is the self pace training module It came with fluke 88 operation video Then a test, a battery, diode, resistor, printed circuit board After watching the video you take the test and mail it in Along with my 88 I have inductive tach adapter Fluke pressure vacuum transducer Contact temperature thermal couple with air liquid contact tips Inductive amp meter $$$$ not a cheap tool Get a few extra amp fuses for the amp circuit

@richard1835 6 ай бұрын

The 9.51 minimum voltage you are showing is the cranking of the engine with the battery dropping to 9.51v before the engine starts correct? Then of course you have your charging voltage. Thank you Pete.

@66crush9 2 жыл бұрын

To clarify what they mean by True RMS. True RMS, VRMS, ARMS and WRMS is the RMS measure of both the AC + DC components, it's integration of the area under the curve. This meter measures VACrms and AACrms, so it separates the DC component. It should state TRUE AC RMS, but like most meter manufacturers, they don't. There's a lot of misunderstanding on this thanks to marketing in companies. Take a look at a Fluke 187 or 189 where they actually measure TRUE RMS, but on the meter they call it AC+DC (in Blue). Most people are fine with this, since they typically measure line voltage or clean DC (battery or SMPS supplied). However, measure a DC source with high ripple current and you will not get a real measure, such as in automotive battery chargers that use a linear charger (large transformer based, not SMPS). Knowing the True RMS allows you to properly design for things such as thermal, efficiency and safety (fuses, breakers, thermal cutoffs, etc..) and to prevent over charging or over powering a battery or device. Class 2 devices, as those that fall under UL1310, have to comply to VRMS up to 2kHz for both indoor and outdoor ratings. Landscape lighting, LV pool lighting, USB 3.x Power Port also must comply. The reason for this in LV applications is because of the breakdown voltage of the skin. How to tell, if the AC symbol on the display only has a tilde ~ it's ACrms. If it has both the tilde ~ and a straight line - above it, its RMS. Some meters (Fluke 187, 189, 287 & 289) use the DC for both DC and RMS, so it will have both if the second function feature is RMS. The Dashed straight line on the flukes means it can also properly measure pulsed DC.

@mike-yp1uk 2 жыл бұрын

My friend got 8 volts on his fuel pump but when I hooked up my scope you could see the computer duty cycle and the correct voltage and ground.

@nic63impss 2 жыл бұрын

Great info

@michaelkeymont501 Жыл бұрын

I’ve had my Fluke 77 for over 25 years, and I got it used…

@acchaladka 5 жыл бұрын

Thanks for this great information. I just got my first Multimeter and realized I have a Cat III 600 volts, not 1000. I’m going to use mine at home on a 1989 Porsche 944 and a 2012 Prius, and around the house. Do I need to return / exchange my unit for 1000 v, or am I alright as long as I don’t use this for heavy duty vehicles?

@MotorAgeMagazine 5 жыл бұрын

The voltage rating is for High Voltage systems like you would encounter on a hybrid or electric vehicle. The leads, too, must be rated CAT III before trying to measure these systems - along with training in safety around them. If you're going to try and work on the HV components, I'd trade it in for the 1000 v model.

@acchaladka 5 жыл бұрын

@@MotorAgeMagazine That's a fantastic response; thank you very much again for all the great training in these videos.

@josephpizzano5953 Жыл бұрын

Maybe consider camera angles as your large hands completely blocked the view of multimeter lead(s) placement on the tiny fuses for the novices out there. Otherwise outstanding presentation thank you very much.

@philh9238 6 жыл бұрын

also how do you do the voltage drop test with the fuses with the plastic caps on them?? i think there called j case fuses

@MotorAgeMagazine 6 жыл бұрын

If you mean the clear caps, you can remove them if need be. The fuse method for locating drains is only one method, and a pretty good one, that can be added to the other ways for testing for drain. Use the one best suited to your situation.

@mike-yp1uk 2 жыл бұрын

If you get a low voltage switch to duty cycle or percent because a computer could be operating it and you might think it's a voltage drop

@boybravo689 3 жыл бұрын

Sir I wacth your presentation regarding parasitic draw in a circuit you put one lead of the meter to one end and the other lead to opposite lead and there's a voltage drop it's my assumption is correct tnx Sir

@MotorAgeMagazine 3 жыл бұрын

If you mean the demo I did in this video, yes - we are measuring the voltage drop across the fuse. No voltage drop - No current flow is occurring. If a voltage drop is measured when the circuit(s) are supposed to be off - that's where the problem is.

@boybravo689 3 жыл бұрын

@@MotorAgeMagazine Tnx for reply Sir

@philh9238 6 жыл бұрын

what about a test light to be the first electrical diag piece equiptment to grab

@MotorAgeMagazine 6 жыл бұрын

I use a test light in a later video, but primarily to show how it can lead some down the wrong path. You can't test a loaded circuit with one or get a good feel for any unwanted resistance that may be present. Just my opinion....

@DeanLangley Жыл бұрын

Triplett has high quality meters at a much better price. Ideal is good too. The Chinese are making meters with the same features. If you ever open your Fluke meter you will be surprised to find a small circuit board with very little on it. What you are looking for in a meter is the insulating quality of the case and leads. Is that insulation really CAT III? And is the the true RMS really true?

@frankdavidson9675 Жыл бұрын

i built my first meter as aheath kit in mail order basic elec course an analog that i used for years a meter will not lie (you can trust it ) that was back in 1965 ihavseveral digital meters now but i still use the analog when testing condensers the needle is better

@curtpiazza1688 2 жыл бұрын

👍

@vikinghauler3244 4 жыл бұрын

Have you seen a particular alternator develop a load within so that with ignition off(maybe ign. on I can't remember,engine was off) you get a reading from case to battery ground maybe as hi as 85 to 90 % of supply voltage

@LAnonHubbard 5 жыл бұрын

16:10 so that 10A fuse had a resistance of 7.4milli Ohm? Just making sure I'm understanding correct.

@MotorAgeMagazine 5 жыл бұрын

If that's the number you come up with when plugging it into Ohms Law! Me personally? I could care less - if there is voltage drop across the fuse, current is flowing. And if there isn't supposed to be current flowing, I know where to start looking for the draw...

@LAnonHubbard 5 жыл бұрын

@@MotorAgeMagazine I guess it doesn't hurt to understand a little more about the maths if you want (which I do), though I get the point about it not making a difference in the context of diagnosing what's drawing current when it shouldn't be.

@boybravo689 3 жыл бұрын

Sir may I know if we can used the current clamp to monitor the parasitic draw when looking for a circuit that have a parasitic draw tnx Sir

@MotorAgeMagazine 3 жыл бұрын

Parasitic draws can be very small. You can use a low amp current clamp and your meter, but both tools have to be fairly good ones to be accurate.

@boybravo689 3 жыл бұрын

@@MotorAgeMagazine Sir your reply much appreciated tnx

@whitetiger8652 6 жыл бұрын

Thanks Pete. Debating on the 88v or 87v.

@bradhobbs6869 6 жыл бұрын

White Tiger

@707SonomaComa 6 жыл бұрын

I think the 87V is true RMS, the 88V is not.

@automedic9781 4 жыл бұрын

707SonomaComa I just got the 87V for just that reason And for 4 years before that I had a Fluke 115 True RMS

@200xcBruce 5 жыл бұрын

I find it kind of interesting you never mention what everyone should know you never mention the voltage is DC

@abdouliejallow7642 6 жыл бұрын

Auto ranging meters are not good for hands on beginners

@707SonomaComa 6 жыл бұрын

Abdoulie Jallow, why not?

@abdouliejallow7642 6 жыл бұрын

i think is complicated and difficult to learn not sure too.

@abdouliejallow7642 6 жыл бұрын

it makes things easier and it does many things for you insted u doing things fot your self.

@bigcountry4262 2 жыл бұрын

Show the meter. Too much lecturing

@paulna5526 3 жыл бұрын

flukes prices are totally ridiculours and total bs, nothing but a greedy company, that's all they are.

@MsJohnaldred 5 жыл бұрын

5 min. Video drug out to 18 min. I recommend watch at 2 times speed.

@brenthoadley2943 Жыл бұрын

Fluke is also woke

@TheHortond 10 ай бұрын

EV is a fad. It will fail like it did 100 years ago.