Multimeter use

[Okie]

I've noticed that if someone does not know how something works it's lots harder for them to attempt tests or repairs, especially electrical testing.
(and you are MOST LIKELY going to ZAP a electrical tester when first learning)
Best to not have lots of money attached to a DMM or VOM when first learning.

I'm a registered electrician, first class electronic tech and mechanic for several years and have all kinds of electrical testers that I have accumulated over the years, some very expensive and several flukes. (and no one else is allowed to touch my electrical testers)

For testing automotive and small engine type stuff I reach for my UEI DL49. It's auto ranging, reads to 400 amps DC or AC by just clamping around the wire. It turns itself off if not used in about 5 min's. I've bought them used for others to use from around $25-50 on fleece bay. They cost around $100 when new and came with test leads, owners manual and nylon carrying pouch.. UEI no longer makes them, but they can be found. Their is also a Craftsman/Sears that has same functions, model 82369 and it sold new for around $65.
If you zap or loose one of these DMM's you have not lost a lot of $$'S as compared to a expensive Fluke. You can go to wal-mart and get a $20 analog meter that has rotary scales and get by until you get more familiar with what you need to test electrically.
I cannot recommend the HF DMM's or VOM's because they are dangerous to the Operator and can be a burn or explosion hazard if set on the wrong scale when testing even 120 volts.

Most generally what zaps electrical testers is the Operator has the meter set to OHMS and then tests VOLTS and the tester is then zapped and the HF's may explode. (even experienced Operators has had this happen and if they say they have not they are not truthful)
Flukes are good test eq but I cannot recommend them as learning tools for Grasshoppers.

Another good to have handy dandy tester that is bullet proof around automotive and small engines is a automotive battery load tester at around $40-100. Harbor Freight has a 100 amp one that is reasonably priced or Napa at around $80.

The computer is your friend when wanting to get idea how to electrically use a VOM or DMM to test things.

 

[Jeff Lary]

I am closing in on a decision. Remember I am a guy that does not even know which outlet to plug in the black or red lead into. I am pretty ok at lots of things, but electricity is not one of them.
As an example, I know Snap On is great stuff, but I have a lot of old pre 1960 Craftsman tools, and they have never failed me. I know you can always buy better but I need to be realistic in my abilities.
This all a preamble to tell you that I thank you for all the advice, but I will likely get a Thsinde (who the hell is that company bty??) or a Crenova (also who ever heard of this one either, besides you guys' ha ha). The point is why do I need a Corvette when a ford fusion will get me there too.

1) Now my next question is "Auto ranging" (I think that is the right term)... does that mean I will not have to remember to select the next highest voltage than the one I expect to find? What I mean is I remember on the HF if I was testing something that was 12v I needed to remember to set the dial to 20v so I did not burn something out.

2) Also, how will I know which position the leads should be plugged into on the unit?

3) Lastly with the Thsinde and the Cernova are the leads that come with the units good enough? or will I need to find some better ones and if I do which ones are better.

 

[Mad Professor]

Well first off thank you to everyone who responded after i hung it up for the night. There are many links here to look at and reviews to research. I will look at / for every model suggested.
I know there are many you tube videos to search for when trying to test for a certain issue. I was just hoping there was some kind of guide that would give examples of how to test for different problems is all.
What I was looking for would have been something like this;
To test starter function, do this.
To test alternator function, do this.
To test for continuity between point a and b do this etc...

I had also looked at Kline back when I first started thinking about getting a worthwhile meter. I have to meet a friend at 8am this morning 40 miles away then when I get back home, I will go back and look through each post and do the research. So, it will be a while before I get back to this thread, but I have not forgotten all you help just need some time to re-read it all.

Do you have the basic knowledge of how electricity/electromagnetism works?

Might be worth spending some evenings in a high school physics text. Then you'll understand volts/amps/ohms, coulombs, resistance, electromagnetism/induced currents, magnetic fields, how electric motors/starters/coils/capacitors work,.......

Maybe $5 at used book store. See if they have the lab manual too. It will explain use of meters.

I still have all my old textbooks.

 

[OM617YOTA]

Here's a video on basics. Haven't watched it, but Will Prowse is solid.

 

[Jeff Lary]

just watched this guy

watching him gave me 2 more questions ,..when he was testing resistance he used an old plug wire. He knew the resistance should be around 10,000 how would a fella " know what to expect to see on the screen for a reading" and second, he was going to measure amps he was choosing between "mA" and "20 A Max" I was wondering how many milliamps there were in an amp. I am guessing a thousand as in 'milli"

 

[RCamo]

The computer is your friend when wanting to get idea how to electrically use a VOM or DMM to test things.

I agree with @Okie 's statement above, there is much good info available but you will have to dedicate some TIME to study and learn. Several others posted good links, here is another: https://www.electronics-tutorials.ws/dccircuits/dcp_1.html which also has a ton of good information on electrical, electronics, etc. Also, Fluke does make good meters and I own a few but you don't need to spend that kind of dough for where you're at right now. You need a SAFE meter which HF is not. Here is a good, relatively inexpensive meter that will do what you need and the capability to do more when you get more experience too. It's what I carry and use for basic electrical troubleshooting. https://smile.amazon.com/UT210D-Dig...0753FY711&psc=1&ref_=pd_bap_d_grid_rp_0_115_t

 

[028S038AV]

I am closing in on a decision. Remember I am a guy that does not even know which outlet to plug in the black or red lead into. I am pretty ok at lots of things, but electricity is not one of them.
As an example, I know Snap On is great stuff, but I have a lot of old pre 1960 Craftsman tools, and they have never failed me. I know you can always buy better but I need to be realistic in my abilities.
This all a preamble to tell you that I thank you for all the advice, but I will likely get a Thsinde (who the hell is that company bty??) or a Crenova (also who ever heard of this one either, besides you guys' ha ha). The point is why do I need a Corvette when a ford fusion will get me there too.

1) Now my next question is "Auto ranging" (I think that is the right term)... does that mean I will not have to remember to select the next highest voltage than the one I expect to find? What I mean is I remember on the HF if I was testing something that was 12v I needed to remember to set the dial to 20v so I did not burn something out.

2) Also, how will I know which position the leads should be plugged into on the unit?

3) Lastly with the Thsinde and the Cernova are the leads that come with the units good enough? or will I need to find some better ones and if I do which ones are better.

Dear Jeff,

Seems like you are getting the idea. Will address some of the above. Also the video you posted and looked at is pretty good. Few thing to answer for the video & maybe a better application for the spark plug and the AMP testing. AMP is current testing, the example he chose was so so (the light bulb)... there are better applications for engines. AMP testing is something you will NOT find or need often.

Yes milli amps is 1/1000 of a amp.
Milliamps you would be testing electronic devices and chips. Again amp is not something you will find often..... but will cover a decent application below for using amps. AMP testing is most likely to fry your meter.

Auto Range.......
Auto Range will select the Voltage or Resistance range for you
nice because you do not need to choose 20V DC to test the car battery. If you chose 2 V DC to set the car 12 V battery it would over range and give you a odd display reading. Auto Range should be a little easier for you AND for life of meter there is less "turning" of the main selector dial on the multimeter. The dial uses a conductive coating under the dial on the PCB, printed circuit board, and this coating can and does wear out from friction and position changes. ONE of the differences between a cheap meter, HF, and better meters are the switches and dial selectors on the meter, how long they will last with selection cycles, etc. This is also the on/off so the main dial gets used a lot. Kinda like a remote that the up channel button would get worn out and needed to press harder and harder and Harder until the up channel no longer workes.... now you need to use the down channel button for your primary selection.

The test leads on the Thinside..... it has 2 sets of test leads for a total of 4 test leads. Ebay also has a selection of test leads for about $7 a set. The provided leads should last 5-10 yrs and are much better than the HF.

The mount position is the Com (common/ground) and the red lead would go in the Ohms/V. These positions allow you to test V, Ohms, point to point continuity. The mA and 20A position is for testing AMPs or the draw of a item or few items. You will not do a lot of AMP testing imo. AMP testing is where it would be more common to fry your meter.

So in your video... Volts are DC and AC. Your home stuff is AC, alternating current and the battery powered stuff like your auto and garden tractor will be DC or direct current. Both deserve respect.

When you do a search..... the "web address" for that search can be shared in a email to friend or post. So you can see the same search pages I got / see. I did 2 searches for topics that may assist your initial knowledge.

using multimeter to check small engines (search link pages of topics)
https://www.youtube.com/results?search_query=using+multimeter+to+check+small+engines
using multimeter to test automotive applications (search link pages of topics)
https://www.youtube.com/results?search_query=using+multimeter+to+test+automotive+applications
Further,
I restore classic autos, fix small engines, all kids of stuff.....
Sometimes you need to get a gauge to work on the dash. Is the sensor, ground, wires, gauge faulty..... I like to make jumper cables with resistors mounted/soldered/covered Heat Shrink to put inline with the wires to gauge. Power the system and can make the coolant or fuel tank gauge move / read. The service manuals will have resistance values for the sensors/coolant/oil press/fuel tank level. This allows tech / you to test the wire harness, gauge, connections, sensor. With out this information you can just swap parts and that is expensive.

Jumpers with alligator clips are good to hold your tester leads on the application while you wiggle wires or do other work. The "jumper" can also have a resistor solder in for test purposes. Common for 50, 100, 200, 300, 500, 1k, 2k, 3k, 5k, 10k. Start with the resistance jumper you need and over time can add to them. The jumper will need to be tested after build and then labeled with paper tag. Advance topic but can save you a great deal of work. Need to understand and read about your gauges.... can burn them out if exposed to too many amps or toooo many volts..... Many times the gauges can be knocked down to 5V not 12V. Again, search your application you need to repair.... forums, manuals, locals, can show what to test and then "just do it" with your new multmeter and new knowledge

Spark Plugs......
Typical for auto spark plugs going from distributor to spark plug will have a resistance value/foot. When I install spark plugs on my classic auto I measure each plug wire. Put on table in order of shortest to longest, then measure the Ohms or resistance of each one and record in your "maint note book" Over time the resistance will grow a bit, with tugging on boots, heat, vibration, temp cycle. When I do tune ups and work and trouble shooting will measure the Spark Plug Wire Resistance again for each wire again, record in my "maint note book" and should be about the same resistance. When you get OPEN, that wire has failed and your spark energy could be way down, because the Spark Energy has to jump the short, to get to spark plug gap and then onto ground in head and onto battery. DC means the energy goes from battery RED to the device to do work, then back thru ground BLACK to the battery. So poor Red or poor Black can hose up your circuits. Another words Grounds are just as important as the Red power wires.

What would be a commont AMP TEST for my auto or tractor.
Lets say we have a short issue and the battery/car dies if I not used for a 3 weeks.
In this case you can set to ..... red test lead to the 20Amp location
Remove the neg/black battery lead, put your meter between the neg cable and neg post on battery. Will show how many mili amps you auto will draw/use when the auto is sitting. Also take time for the auto to go into a sleep mode and turn off all the systems/computers/sensors you may have just woke up with key on/off. When the key is JUST turned off you may see 1-2 amp. Then it will go down, then down again.... after 15 min should be down to 30-35 mili amp depending on the auto. May even go lower or have none. Radio memory is one that comes to mind..... also after market radios can be installed wrong and know for larger AMP draws and killing batteries. So how do we find the draw...... you can pull one fuse at a time of the items you think could be your draw or short. Watch the meter display of amps. Once you testing and are in the mili amp range..... you could take out of neg battery service, turn off meter, and change to mili amp location if you need better resolution. May or may not be necessary. This is a pretty cool test.... I have done 2-3 times in the past 10 yrs. There are videos showing more of this too.

Class is over.... time to send you a bill.... he hee
Spent my life helping large companies pick their tools, production, and design their products better as a supplier. I am a engineer and spent my life helping engineers do their job better.

 

[ElevatorGuy]

I’ve used my fluke every work day for 12 years. Years ago I bought a craftsman meter for $10. I’ll still occasionally get that out but only for batteries or low voltage dc stuff.

 

[Jeff Lary]

Dear Jeff,

Seems like you are getting the idea. Will address some of the above. Also the video you posted and looked at is pretty good. Few thing to answer for the video & maybe a better application for the spark plug and the AMP testing. AMP is current testing, the example he chose was so so (the light bulb)... there are better applications for engines. AMP testing is something you will NOT find or need often.

Yes milli amps is 1/1000 of a amp.
Milliamps you would be testing electronic devices and chips. Again amp is not something you will find often..... but will cover a decent application below for using amps. AMP testing is most likely to fry your meter.

Auto Range.......
Auto Range will select the Voltage or Resistance range for you
nice because you do not need to choose 20V DC to test the car battery. If you chose 2 V DC to set the car 12 V battery it would over range and give you a odd display reading. Auto Range should be a little easier for you AND for life of meter there is less "turning" of the main selector dial on the multimeter. The dial uses a conductive coating under the dial on the PCB, printed circuit board, and this coating can and does wear out from friction and position changes. ONE of the differences between a cheap meter, HF, and better meters are the switches and dial selectors on the meter, how long they will last with selection cycles, etc. This is also the on/off so the main dial gets used a lot. Kinda like a remote that the up channel button would get worn out and needed to press harder and harder and Harder until the up channel no longer workes.... now you need to use the down channel button for your primary selection.

The test leads on the Thinside..... it has 2 sets of test leads for a total of 4 test leads. Ebay also has a selection of test leads for about $7 a set. The provided leads should last 5-10 yrs and are much better than the HF.

The mount position is the Com (common/ground) and the red lead would go in the Ohms/V. These positions allow you to test V, Ohms, point to point continuity. The mA and 20A position is for testing AMPs or the draw of a item or few items. You will not do a lot of AMP testing imo. AMP testing is where it would be more common to fry your meter.

So in your video... Volts are DC and AC. Your home stuff is AC, alternating current and the battery powered stuff like your auto and garden tractor will be DC or direct current. Both deserve respect.

When you do a search..... the "web address" for that search can be shared in a email to friend or post. So you can see the same search pages I got / see. I did 2 searches for topics that may assist your initial knowledge.

using multimeter to check small engines (search link pages of topics)
https://www.youtube.com/results?search_query=using+multimeter+to+check+small+engines
using multimeter to test automotive applications (search link pages of topics)
https://www.youtube.com/results?search_query=using+multimeter+to+test+automotive+applications
Further,
I restore classic autos, fix small engines, all kids of stuff.....
Sometimes you need to get a gauge to work on the dash. Is the sensor, ground, wires, gauge faulty..... I like to make jumper cables with resistors mounted/soldered/covered Heat Shrink to put inline with the wires to gauge. Power the system and can make the coolant or fuel tank gauge move / read. The service manuals will have resistance values for the sensors/coolant/oil press/fuel tank level. This allows tech / you to test the wire harness, gauge, connections, sensor. With out this information you can just swap parts and that is expensive.

Jumpers with alligator clips are good to hold your tester leads on the application while you wiggle wires or do other work. The "jumper" can also have a resistor solder in for test purposes. Common for 50, 100, 200, 300, 500, 1k, 2k, 3k, 5k, 10k. Start with the resistance jumper you need and over time can add to them. The jumper will need to be tested after build and then labeled with paper tag. Advance topic but can save you a great deal of work. Need to understand and read about your gauges.... can burn them out if exposed to too many amps or toooo many volts..... Many times the gauges can be knocked down to 5V not 12V. Again, search your application you need to repair.... forums, manuals, locals, can show what to test and then "just do it" with your new multmeter and new knowledge

Spark Plugs......
Typical for auto spark plugs going from distributor to spark plug will have a resistance value/foot. When I install spark plugs on my classic auto I measure each plug wire. Put on table in order of shortest to longest, then measure the Ohms or resistance of each one and record in your "maint note book" Over time the resistance will grow a bit, with tugging on boots, heat, vibration, temp cycle. When I do tune ups and work and trouble shooting will measure the Spark Plug Wire Resistance again for each wire again, record in my "maint note book" and should be about the same resistance. When you get OPEN, that wire has failed and your spark energy could be way down, because the Spark Energy has to jump the short, to get to spark plug gap and then onto ground in head and onto battery. DC means the energy goes from battery RED to the device to do work, then back thru ground BLACK to the battery. So poor Red or poor Black can hose up your circuits. Another words Grounds are just as important as the Red power wires.

What would be a commont AMP TEST for my auto or tractor.
Lets say we have a short issue and the battery/car dies if I not used for a 3 weeks.
In this case you can set to ..... red test lead to the 20Amp location
Remove the neg/black battery lead, put your meter between the neg cable and neg post on battery. Will show how many mili amps you auto will draw/use when the auto is sitting. Also take time for the auto to go into a sleep mode and turn off all the systems/computers/sensors you may have just woke up with key on/off. When the key is JUST turned off you may see 1-2 amp. Then it will go down, then down again.... after 15 min should be down to 30-35 mili amp depending on the auto. May even go lower or have none. Radio memory is one that comes to mind..... also after market radios can be installed wrong and know for larger AMP draws and killing batteries. So how do we find the draw...... you can pull one fuse at a time of the items you think could be your draw or short. Watch the meter display of amps. Once you testing and are in the mili amp range..... you could take out of neg battery service, turn off meter, and change to mili amp location if you need better resolution. May or may not be necessary. This is a pretty cool test.... I have done 2-3 times in the past 10 yrs. There are videos showing more of this too.

Class is over.... time to send you a bill.... he hee
Spent my life helping large companies pick their tools, production, and design their products better as a supplier. I am a engineer and spent my life helping engineers do their job better.

Thank you, I will copy and save your post for future use.

 

[Jeff Lary]

I’ve used my fluke every work day for 12 years. Years ago I bought a craftsman meter for $10. I’ll still occasionally get that out but only for batteries or low voltage dc stuff.

I can see you do this sort of testing work often. I would likely use my tester a few minutes a year.

 

[OM617YOTA]

Make sure you put high quality batteries in your meter, and not Duracells. You don't want to come back to your meter in six months or a year and find the batteries have leaked and damaged your meter.

You can also pull your batteries out of your meter when you're not using it, but that's a pain, especially since many meters have battery compartments held closed with screws.

 

[ZeroJunk]

Usually doesn't matter which way you have the leads. If backwards it will just show a - in front of the number.

 

[just Dave]

I have many free meters (HF)and a couple very nice ones (Fluir). One dig. 1 analog. Working conditions can be brutal, so when cheap will do; it does.
Check a good/new AA, if 1.6 to 1.65 or so the meter is good for most things. Continuity can be tested by touching the 2 leads together, should resolve to 0. Meter is now conformed good that test. I do these tests to any meter I use. If you can not prove it is bad, it is not. HF was giving out free ones for years so I have several and a few have failed, not many.
More money is often spent on items to make a man better at his chosen task, but it is the man(person) that makes the job.

 

[just Dave]

I don’t know how to make quotes stick where I put them but yes Durucell are the leakiest batteries out there.

 

[OM617YOTA]

I have many free meters (HF)and a couple very nice ones (Fluir). One dig. 1 analog. Working conditions can be brutal, so when cheap will do; it does.
Check a good/new AA, if 1.6 to 1.65 or so the meter is good for most things. Continuity can be tested by touching the 2 leads together, should resolve to 0. Meter is now conformed good that test. I do these tests to any meter I use. If you can not prove it is bad, it is not. HF was giving out free ones for years so I have several and a few have failed, not many.
More money is often spent on items to make a man better at his chosen task, but it is the man(person) that makes the job.

I don't necessarily agree. A sufficiently sensitive meter will read the resistance of the leads when the leads are touching, and won't go to zero. Cheap meters can work for sacrificial use, but a high quality meter will out last a thousand of the free HF meters in most situations.

I definitely agree with testing the test equipment first. I once chased an electrical problem around a vehicle with a faulty test light, pulling my hair out, and was unable to nail it down. Got a good test light and had it sorted in five minutes. Never again!

 

[ElevatorGuy]

Another note, analog meters still have a place too. Even a test light sometimes won’t catch a quick flash of voltage. Happens so quickly that even my fluke won’t catch it. An analog meter you’ll see the needle swing no matter how quick the flash is. We have contacts and timers that flash on and off in milliseconds.

 

[028S038AV]

Thank you, I will copy and save your post for future use.

Thank you too.
The two links are for a "search result" in Youtube. Good info to teach about meter use engine/auto

MoYota,
Funny you mention battery issues for multimeters.

That is what took out my nice OLD Realistic Multimeter, battery leaked, traveled down contact to PCB. Flaked it off, tried to neutralize, scrubbed with PCB, looked like good repair, but would not work. Scraped and purchased new meter, followed by 2 more good quality meters.

I also use the HF free meters, but leads keep breaking. Wire breaks off the metal contact probe. Just found if you pull the metal tip out of the plastic handle, it will "yield" the solder contact area for wire..... solder connections pooooor for the 10 or so have looked out. So if you want to repair, this would work. Before i "fumbled" on this, old eyes, just put the leads aside or tossed.

 

[OM617YOTA]

I can't stand the leads on cheap meters. Vinyl insulation, stiff like dry spaghetti when cold, difficult in use, impossible to coil neatly for storage, and subject to breakage.

Leads with silicone insulation are worth the cost. Very flexible, not impacted by cold.

 

[SteveSr]

I don’t know how to make quotes stick where I put them but yes Durucell are the leakiest batteries out there.

Gee, I thought I was the only one! Just about EVERY Duracell I have touched has leaked while still having charge. Some even leaked while in the packaging.

 

[Chevboy0167]

Very good leads here...

https://probemaster.com/8000-series-test-leads-only/

The reason why...