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
121 Comments
Tomi Engdahl says:
Square Wave Generator Mode in Digital Multimeter (DMM) | Observation on DSO
https://www.youtube.com/watch?v=4yfq9YrUUpI
This video will explain about the square wave output feature in digital multimeter, frequency, amplitude observation with the help of DSO.
Tomi Engdahl says:
Why is There a Frequency / Wave Symbol on Multimeter? What is Its Use or Function?
https://www.youtube.com/watch?v=C3EKI83NaPo
We have seen a Frequency/Square Wave Symbol in the Yellow multimeters. But many of us do not know what it actually does. In dotays video I have explained it with practical demo.
Tomi Engdahl says:
https://maker.pro/forums/threads/dvm-meters-with-square-waveform-mode.271344/
Sinometer UT30D Pocket-size Digital Multimeter with 50 Hz Square Wave Generator
Why 50hz squave wave generator? to test what at 50hz squaveform?
Steve check it out again, it’s not an oscope, its a DVM meter with a function mode with a square waveform output at only 50hz
It is right next to the Diode checker mode, it has a square waveform symbol
It only outputs at 50hz at 2 volts peak to peak
My question is the use of this mode? what can you test at 50hz? what circuits can I test using a 50hz square waveform
I heard that one of its use is to test line power transformers, but why would you test a transformer at 50hz? plus if you apply 50hz squarewaveform to the primary how do you measure the secondary of the transformer?
There is other brands of meters like this that output a square waveform at 30hz, but for what kinds of test? to test what at 30hz?
The link points me to a cheap imported 3 1/2 digit multimeter. Maybe the “unique build in square wave generator” could be used to stimulate a circuit? No information on what the peak-to-peak amplitude or current sourcing capability is, but for sixteen bucks (plus shipping and handling) I bet it ain’t much. Probably a left-over from internal clock circuitry.
Now I know what you’re talking about, the answer is simple.
It is a mostly useless feature added to differentiate the multimeter from others. It’s pretty much the same as the transistor tester almost nobody will use it, but it seems like a nice feature to have.
It’s also probably cheaper and easier than a frequency or counter option and maybe people will think that’s what it is.
No, it’s ment for testing or injecting into an input or circuit
1.) To test transformers, how can you?
2.) PWM motors , it’s ment for PWM circuits but how so?
3.) Adjustable voltage control circuits?
4.) Synchronic clock?
5.) Calibrate flow meter displays?
6.) Tachometers
7.) Frequency input devices
Look at PAGE#31 of the BK meter it explains it B&K Precision Corp.’sModel 2890A
https://bkpmedia.s3.amazonaws.com/downloads/manuals/en-us/2890A_manual.pdf
Well there’s your answer. Congratulations.
1.) I put a 50hz square waveform on the primary of the transformer and use an oscilloscope on the secondary?
why is 50hz a good test frequency for transformers?
2.) 50hz to test a PWM circuit ? to see if the PWM circuit is outputting a waveform on the oscilloscope?
3.) not sure what an adjustable voltage control circuit is or does or what is it used for
4.) Synchronic clock, i have no idea what this is or used for
5.) Calibrating a flow meter display using a square waveform out?
6.) Testing a Tachometer using a 50hz square waveform, i have no idea how this is done
Why do you think 50Hz might be a good frequency?
I have no idea why, why do you think it’s a good frequency?
I would think 60hz because it’s line frequency ,
but 50hz might work for testing line power transformers
The other DVM meters are at 30hz, which I have no idea what to test at 30hz
The BK meter is the only one that is a variable frequency and duty cycle square waveform output
Would it be equally good for all transformers?
No, just for 60hz line power transformers
not for testing audio transformers or output transformers
Maybe for step up and down transformers
What output would you expect to see on the secondary?
The same waveform on the primary to the secondary, same voltage and line frequency
Just because some instrument has a “feature” doesn’t mean that “feature” is useful. If I want a variable frequency, variable duty cycle waveform to test something I also want to (1) be able to select the waveform (2) adjust the frequency and (3) set the duty cycle (or pulse width)… preferably with knobs not buttons. But that’s just me. A dedicated function generator, not a multi-meter, is what I would use.
Transformers don’t pass square waves very well, so I fail to see how exciting their primary with a square wave would provide much useful information measured at the secondary. YMMV.
Why do you think 50Hz might be a good frequency?
I have no idea why, why do you think it’s a good frequency?
I would think 60hz because it’s line frequency ,
but 50hz might work for testing line power transformers
Mains / line frequency is 50 Hz in many places outside the U.S. including the UK, Europe and Oceania. In any case 50 Hz is not too far from 60 Hz. So that might be the right answer – that the meter might be slightly useful for testing mains (line) transformers.
What output would you expect to see on the secondary?
The same waveform on the primary to the secondary, same voltage and line frequency
Different voltage, unless the transformer has a 1:1 turns ratio.
Same frequency, yes.
The transformer will change the waveform too. A transformer that’s designed to operate at 50/60 Hz is designed to pass a sinewave, not a squarewave. A squarewave has lots of harmonics, which (by definition) are at higher frequencies than the fundamental, and a mains (line) transformer will not reproduce these very well.
If you have one of these meters, and an oscilloscope, you can do an experiment to see how the transformer modifies the squarewave.
Tomi Engdahl says:
https://lygte-info.dk/review/DMMMustool%20MT108T%20UK.html
Tomi Engdahl says:
https://www.eevblog.com/forum/testgear/uni-t-ut33d-very-low-cost-multimeter-teardown-and-review/
Tomi Engdahl says:
#514 UNI-T UT120C Pocket Multimeter
https://www.youtube.com/watch?v=69RjUVNkDpI
Tomi Engdahl says:
What On Earth Is Diode Mode On A Multimeter? How Do I Use It? Why Is It So Cool?
https://www.youtube.com/watch?v=HJVNI_WeTvE
Tomi Engdahl says:
Multimeters (DMM) and their chips, with computer communication
http://www.improwis.com/projects/reveng_multimeters/
http://www.improwis.com/projects/reveng_multimeters/#Schematics
Tomi Engdahl says:
121GW Multimeter REVIEW [2023]
https://www.youtube.com/watch?v=1iqURp-NsdM
I take a detailed look at the 121GW from Dave Jones of EEVBlog and compare with the Fluke 116, Fluke 8845A, DE-5000 and M-830B.
INDEX
0:00 — Intro
2:20 — Unboxing
3:17 — Manuals & Add-ons
4:01 — Power ON & Firmware
5:49 — Battery Life
6:27 — Changing Batteries & SD Card Slot
8:20 — Auto Power Off (APO)
11:29 — LCD Contrast
13:33 — LCD Cover Issues
16:33 — Kick Stand, Probe Holders & Wobble Woes
19:08 — Included Probes
21:35 — Typical Uses for DMMs
21:57 — Continuity Checking
27:19 — 50,000 Count Display & Resistivity Measuring
35:09 — AC Voltage Measurements
35:59 — DC Voltage Measurements
36:34 — DC Current Measurements
43:33 — Capacitance Measurements
51:20 — Data Logging
1:00:23 — Secondary Display, Mode Memory, Dual Temp. Sensing
1:03:59 — 15V Diode Test (Zeners)
1:05:20 — Volt Amp (Watts DC) Measurements
1:06:17 — Frequency Measurements
1:06:53 — Closing Thoughts
Tomi Engdahl says:
Digitaalinen yleismittari True RMS UNI-T UT161D
https://www.clasohlson.com/fi/Digitaalinen-yleismittari-True-RMS-UNI-T-UT161D-/p/36-8255
Tomi Engdahl says:
https://hackaday.com/2019/12/22/is-that-cheap-multimeter-as-good-as-a-fluke-lets-find-out/
Tomi Engdahl says:
Teardown Of A UNI-T UT61E+ True RMS Multimeter
http://www.kerrywong.com/2021/04/04/teardown-of-a-uni-t-ut61e-true-rms-multimeter/
Tomi Engdahl says:
Test screwdriver with microcontroller!
https://www.youtube.com/watch?v=6fCiZ5kTDso
This is NOT the product I was expecting. The functionality is probably the same, but the circuitry is very different, and it seems ridiculous that a microcontroller could be used in this application. Especially when you see how they detect the voltage thresholds.
I get the impression from the ludicrous 100Mohm resistor that the circuit is just using a simple threshold system where an internal weak pull-up is used on a digital input so that a test voltage of two distinct thresholds will be detected for continuity and high voltage.
It’s quite odd that one LED goes to positive and one to negative. But there are lots of oddities about the design, which could easily have been implemented on a single sided PCB.
Quiescent current is spectacularly low, so the cell stack should last a reasonable amount of time.
Although the standby current of 7uA drops to near zero after about 9 seconds when the chip goes to sleep, it was notable that a noisy electrical load in the vicinity kept it awake and drawing about 20uA.
The microcontroller seems to waken and check the inputs briefly in standby, as tapping the end of the driver is not initially detected until it coincides with a wake-up and the microcontroller goes into sense mode.
Tomi Engdahl says:
Simple Transistor Tester Circuit for PNP & NPN Transistors
https://www.elprocus.com/simple-transistor-tester-circuit/
Tomi Engdahl says:
https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/
Tomi Engdahl says:
Why The Clamp Meter Is The Only Tester You Need | Pros and DIYers
https://www.youtube.com/watch?v=kawFTI5-kqU
Over the last 10-15 years clamp meters have come a long way and added a ton of features. So much so that a clamp meter is pretty much all you need for residential electrical work. In this video, I will demonstrate the Klein Tools CL120 and how this one piece of hardware can cover 95% of your testing needs.
Tomi Engdahl says:
[US$92.00 54% OFF]TOOLTOP ET11S/ET12S 2In1 Thermal Imager Digital Multimeter 6000 Count Voltage Current Resistance Capacitance Diode Frequency Tester PC Data Transfer Measurement & Analysis Instruments from Tools on banggood
https://ban.ggood.vip/14nr7
Tomi Engdahl says:
Multimeter
https://hackaday.io/project/195109-multimeter
This is my attempt at designing a basic USB powered multimeter. Included modes are VDC, Ohms, and (Capacitance).
Tomi Engdahl says:
EEVblog 1574 – REVIEW: Is the $42 Fluke 101 Multimeter Any Good?
https://www.youtube.com/watch?v=ymJc5oxthlw
Tomi Engdahl says:
EEVblog 1447 – EXPENSIVE Fluke vs CHEAPER Brymen – Teardown
https://www.youtube.com/watch?v=3Hlmq57FQQk
Tomi Engdahl says:
I don’t think it’s “overengineered.” I think it’s a good way to prevent burning out the fuse.
https://m.youtube.com/shorts/UzvAaeE_Gog?si=5-4_JsB7VltAZ4TF&fbclid=IwZXh0bgNhZW0CMTEAAR0aVHMjc-c_D3-gGFjpOFHr9ZYTc0JNsaObgBQ-TXOOHtVVuKhLISsfCng_aem_1O97W-h_F0x8F6xqrDS1fg