Are you planning to buy a multimeter and need help? Here are some timps
How to Buy a Multimeter covers what you need to know to select a meter for DIY electronics. It focuses on the needs for audio electronics, but it’s purposely kept general in nature.
Handheld Digital Multimeters are mainly used to measure resistance, as well as DC/AC voltage and current. Common multimeters can be divided into two types, desktop and handheld digital multimeters depending on their sizes. A handheld digital multimeter is basically composed of Analogue Front End (AFE), MCU, Human-machine interface and Power supply. The design of handheld multimeters should focus on the features of low power, high performance and compact size.
Look for these features when buying a multimeter article tells that multimeters can be handy for troubleshooting PC power problems (I would say it is a must have). But the range of features and prices can be confusing when you’re shopping for one. Before you waste time and money, find out which features are essential and which are merely nice to have.
EEVblog #75 – Digital Multimeter Buying Guide for Beginners
EEVblog #91 – $50 Multimeter Shootout – Extech EX330, Amprobe AM220, Elenco, Vichy VC99, GS Pro-50
$50 Multimeter Comparison and Teardown article tells about a very nice video series on multimeters. Here is maybe the most interesting video from it:
$50 Multimeter Shootout – Part 7 – 15 DMMs Compared! – Teardowns – #0074
71 Comments
Tomi Engdahl says:
Can a multimeter shock you?
Shock hazards can occur if the meter and test leads are not properly maintained. Arc flash can occur if the meter is not properly rated for the voltage, the meter is exposed to transient voltages outside of its operating conditions, or because of defective parts or components.
https://leafelectricalsafety.com/blog/digital-multimeter-danger
Tomi Engdahl says:
Best Safety Tips For Using a Multimeter
Tip 1: Choose the Right Meter.
Tip 2: Examine The Meter Before Using It.
Tip 3: Examine The Test Probes.
Tip 5: Understand The Dangers.
Tip 6: Know the CAT Ratings.
Tip 7: Know The Voltage Ratings.
https://medium.com/@multimeterpro/how-to-use-multimeter-safely-3fe4bd418ce9
Tomi Engdahl says:
Inside a cheap multi-voltage tester (with schematic)
https://www.youtube.com/watch?v=JSLHxKM-kpw
If I had to have a single test tool for electrical maintenance work it would be a voltage tester (test lamp) as they are the best way to check for the presence of voltage reliably by applying a load to the circuit being tested.
Normally I’d suggest a Fluke tester for professional work, but for home use by DIYers or trades that might not use them so much, I’d suggest a cheap and simple set like these.
The cheap sets actually have a big advantage over the higher profile brands in that they often power themselves directly from the circuit, and in doing so load it down enough to shunt stray capacitively coupled leakage current that can cause false readings on some more sophisticated and expensive testers. It also means you don’t have to worry about batteries going flat or leaking and destroying the tester.
That does also mean that these pass enough current to give a strong shock if you hold the end of a probe while sticking the other into a live connection. Use them with suitable caution.
The circuitry in this unit is quite sophisticated, but does lack the reassurance of a fuse. As such I’d only recommend its use on lower energy circuits like home circuits beyond the distribution board, and not in high current industrial equipment. Use a Fluke for the industrial stuff to “tick the box”.
If one of the four rectifier diodes failed in this tester it could cause a high current fault with nothing but the tracks as fuses, and that might not deal with the fault as well as a proper HRC fuse.
The diodes could also have been spaced a little further apart, as the DC side does have full mains potential across it.
The tester does come with tip covers (which you will lose) but does not have shrouds around the probes so only the tips are exposed. I’d suggest adding a bit of sleeving if using in areas where you could bridge onto adjacent grounded metal or other connections.
Tomi Engdahl says:
eevBLAB 87 – Flake Multimeter Watch!
https://www.youtube.com/watch?v=YxyW_mttnQ0
Shut up and take my money!
A look at the Flake Multimeter Watch concept art by Alexander Schmid
Fluke should hire this guy!
FLAKE True RMS Multimeter Watch
https://www.youtube.com/watch?v=7zVlCvV662o
This is a demonstration of the quality and creativity of my work as a 3D artist. The combination of a measuring instrument with a comfortable to wear watch. Knowing the time while measuring some voltage may be essential in some situations…
Do you want to present your imaginary product? Contact me for more information.
Tomi Engdahl says:
Some cheap multimeters use bad old fashioned AC measurement circuits that does not measure just AC part, but also takes into account DC (with wrong scaling factor).
https://edadocs.software.keysight.com/kkbopen/digital-multimeter-ac-measurement-considerations-589742414.html
Tomi Engdahl says:
Digital Multimeter AC Measurement Considerations
https://edadocs.software.keysight.com/kkbopen/digital-multimeter-ac-measurement-considerations-589742414.html
Tomi Engdahl says:
Lopeta tämän yleismittarin käyttö heti: ”Voi johtaa vakavaan ruumiinvammaan tai jopa kuolemaan” https://www.is.fi/digitoday/art-2000009464280.html
SÄHKÖTEKNIIKAN laitteita valmistava Fluke Corporation vetää takaisin Amprobe-tuotemerkin yleismittareita. Yhtiö julkaisi tiedotteen (pdf) takaisinvedosta, ja asiasta uutisoi myös Turvallisuus- ja kemikaalivirasto Tukes.
Vika koskee seuraavia malleja:
AM-500-EUR
AM-500-EUR KIT
AM-510-EUR
AM-510-EUR KIT
HEX60-DTakaisinvedon piirissä ovat sarjanumerot välillä 535900001–587799999 ja mikä tahansa muu sarjanumero, joka alkaa muulla kuin numerolla 5. Jos sarjanumero puuttuu tai siitä ei saa selvää, laite kuuluu takaisinvedon piiriin.
Tomi Engdahl says:
Sähköiskun vaara: Onko sinulla tämä yleismittari? https://www.is.fi/digitoday/art-2000008617978.html
SÄHKÖTEKNIIKAN laitteita valmistava Fluke Corporation varoittaa Fluke 8X V -sarjan digitaalisista yleismittareistaan. Niissä on mahdollinen turvaongelma, joka voi pahimmillaan altistaa sähköiskulle.
Tomi Engdahl says:
How to use your trashy meter without blowing it up (much)
https://www.youtube.com/watch?v=-QDW0LRQVrY
Your first multimeter can initially seem a bit daunting with all the modes, but the only way to learn is to get one and play with it. I damaged my first meter when I was young by using it on the incorrect range. You can damage these cheap meters, but at the cost you don’t have to worry about it too much.
I probably made this video too long and complicated, but it’s useful to know how things work as well as how to use them.
The very cheap meters sold for around 5 $/£/€ are usually pretty accurate for their cost and very usable. Once you’ve mastered using one you can move up to something with more features or more suitable for industrial work. These cheap meters are NOT suitable for poking around in distribution boards or industrial equipment with high fault current.
Meters have a category rating as follows:-
Cat I – electronic use (these cheap meters)
Cat II – electrical appliance, but not fixed wiring or distribution boards
Cat III – general electrical maintenance in panels and machines
Cat IV – utility level work with very high fault currents
For industrial work I recommend Fluke as it appeases the clipboard warriors. There are many other brands suited to industrial use too. Beware cheap meters with fake category ratings.
The Fluke meter in the video is an original American made unit, and was my first ever real industrial meter. It cost a lot, but has lasted well.
I recommend getting these meters from a prominent supplier in your country to ensure they comply with local regulations. The one I demonstrated is from CPC/Farnell and definitely better quality than the eBay imports.
Tomi Engdahl says:
https://hackaday.com/2023/04/10/your-multimeter-might-be-lying-to-you/
Tomi Engdahl says:
https://lygte-info.dk/info/DMMReviews.html
Tomi Engdahl says:
How to Turn Off Ghost Voltages with Dual Impedance (LoZ) Meters
https://www.youtube.com/watch?v=JRXTFxsA_lA
Tomi Engdahl says:
In the Know: LoZ and Ghost Voltages
https://www.youtube.com/watch?v=jWc6LfJtbqw
What is Ghost Voltage?
https://www.youtube.com/watch?v=gVi9I7-KJfU
Tomi Engdahl says:
How To Determine If Voltage Is Real Or a Ghost Voltage Using your Fluke Digital Multimeter
https://www.youtube.com/watch?v=mRwsxmn2P-s
In this video, you’ll learn how to determine if voltage is real or a ghost voltage.
Ghost voltages are caused when energized circuits and nonenergized wiring are located in close proximity to each other, such as in the same conduit or raceway. This condition forms a capacitor and allows capacitive coupling between the energized wiring and the adjacent unused wiring.
When you place your multimeter leads between the open circuit and the neutral conductor, you effectively complete the circuit through the input of the multimeter. The capacitance between the connected, hot conductor and the floating conductor forms a voltage divider in conjunction with the multimeter input impedance. The multimeter then measures and displays the resulting voltage value.
Most digital multimeters today have an input impedance that’s high enough to show this ghost voltage, giving a false impression of a live conductor. The meter is actually measuring voltage coupled into the disconnected conductor. But at times, these voltages can be 80-85 % of what the “hard” voltage should be. If not recognized as a ghost voltage, additional time, effort and money will be lost troubleshooting circuit problems.
Tomi Engdahl says:
How to Calibrate Inexpensive Multimeters
https://www.youtube.com/watch?v=-izNaaLWG1k
Here is how to calibrate low-cost multimeters. This is very simple and only takes about 10 minutes with the right equipment.
Tomi Engdahl says:
HOW TO FIX A MULTIMETER THAT DOES NOT WORK (MY TOP 3 PROBLEMS & REPAIRS)
https://www.youtube.com/watch?v=zBXfmXwBsww
In this video we look at common issues with multimeters.
Tomi Engdahl says:
https://www.eevblog.com/forum/testgear/are-uni-t-multimeters-any-good/
Uni-T is one of the two principal multimeter makers in China, the other one being Mastech.
The company is privately owned and based in Hong Kong, with manufacturing done in mainland China.
Since their main market is China itself and emerging economies, their equipment is built to a price, with varying levels of quality.
In general, the quality is acceptable, considering the low price.
Be aware that input protection on most of their devices has been minimal, without much respect for updated international norms.
I have tested my UNI-T multimeters on mains (240VAC), on all possible selections. UT71B/D and UT61E survived without a whimper of protest, even the pocket-size UT120. No life changing experience yet.
Having said that, input protection is minimal and staying away from the mains is a good idea.
There are no fuses in the 120C. Just a self recovery 250V 400mA overcurrent protector (WH250 400) (Polyswitch).
It is rated for 250V, so should be able to handle the mains on it, but I don’t want to damage the meter, in case it doesn’t.
I don’t expect anything drastic to happen though.
No, to all meters, of course, but the Uni-Ts are not build that well regarding safety.
Fluke has a nice document called “ABCs of multimeter safety” which explains this stuff quite well.
It is better to assume that any multimeter that is not a Fluke, Agilent, and possibly Brymen, is not safe until shown otherwise. I have not see one, not one Uni-T that actually has proper input protection. I will believe this meter owned by the OP is not safe for mains until I see the insides. This will be a belief based on the track record of the manufacturer.
Tomi Engdahl says:
The history of the multimeter
https://www.fluke.com/en-us/learn/blog/digital-multimeters/multimeter-history
When was the multimeter invented?
The first device that could be considered a predecessor to the multimeter showed up in 1820 It was a moving-pointer current-detecting device, called a galvanometer. Designed only to detect electrical current and could make a compass needle move, the galvanometer was useful in the lab, but very bulky and delicate, so impractical for fieldwork.
Who invented the first multimeter?
In 1920, a British Post Office engineer, Donald Macadie, is credited with inventing the very first multimeter. The story goes that he was frustrated that he needed to carry a bunch of different tools when working on telecom lines, so he created one tool that could measure amperes, volts, and ohms. Leading to the product being named the AVOmeter.
The first AVOmeter itself was quite clunky compared to the digital multimeters we are used to today. But over the first decade of the multimeter’s life, it shrunk considerably, creating a portable version with additional range and features by the 1930s.
The history of the voltmeter really picks up when Westinghouse introduced the first Universal meter. The original AVOmeters only measured direct current (DC), resistance, and voltage in 13 different ranges. When the “copper oxide instrument rectifier” was made, the meter featured the ability to measure alternating current (AC) and upped the ranges from 13 to 20.
The Fluke 8020A digital multimeter
The world’s first successful handheld digital multimeter, or a voltmeter with multimeter features — gave field technicians the troubleshooting capabilities once reserved for lab specialists. The Fluke 8020A digital multimeter made big news in 1977.
It changed Fluke’s focus from a maker of bench test instruments into the world leader in handheld electrical test tools.
Tomi Engdahl says:
#7 Best Cheap Multimeters (For Electronics & Cars, 2023)
https://www.yamanelectronics.com/best-cheap-multimeters-cars/
Tomi Engdahl says:
7 Best Multimeters in 2023
https://www.gadgetreview.com/best-multimeter
The best multimeter we tried was easily the Fluke 115 Compact True-RMS Digital Multimeter. This multimeter accurately measures true root mean square (RMS) voltage, resistance, continuity, frequency and capacitance, with a CAT III 600 V safety rating and a bright LED backlight for working in dimly lit areas. A multimeter is a top-rated tool that all electricians or DIY enthusiasts should have in their tool box.
Tomi Engdahl says:
5 Best Multimeters (2023 Guide)
https://www.thisoldhouse.com/tools/23276192/best-multimeter