Single universal measurement device that can be used to measure voltage [V] and current [A] in both AC and DC, as well as resistance [Ω]. Often many other ranges are available like frequency [Hz], duty cycle [%], capacity [F], ... Most are hand held, some more expensive ones come as a bench model.

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532 views

Multimeter into wall sockets

If you placed one of the multimeter's probes into the hot slot of the wall outlet and touched the other probe to your skin while grounded, for example to some dirt outside, would you get bitten by the ...
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1answer
117 views

Why is this multimeter power supply short circuit when off

I have just been following some traces around inside an old digital multimeter (AVO DA116). I was poking around at the LCD driver chips (MC14543CP) when I noticed that the power supply was short ...
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1answer
40 views

power supply multimeter voltage test differ from the label

I have a router's power supply. 12 Volts is written on the label. When I use a multimeter the voltage is 16.80V. Should I use it to power a small LED strip that requires 12V?
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2answers
61 views

How do I calculate the frequency accuracy of a Fluke DMM?

I have a Fluke 8846A and I want to make a frequency measurement with an error less than 1 mHz. I'm having trouble interpreting the manual as to calculate the error of a 120V 60Hz measurement. ...
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2answers
85 views

Can a digital multimeter damage a powered circuit when measuring resistance?

I wanted to make sure my ESD wrist-strap is in working order. So I tested like this: Connected the wrist-strap to household ground (via wall socket). Measured the resistance between the wrist-strap ...
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2answers
87 views

New multimeter probes don't fit my multimeter

This seems like a silly question, but my research is failing to yield results... I ordered some new probes for my multimeter because I needed things like alligator clip leads and the little wire ...
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3answers
145 views

How does a flame sensor or thermocouple operate with just one wire?

I am learning electronics and I just got stumped. I was just looking at a flame sensor and it appears to have only has one connector. I thought sensors in general need two wires to form a complete ...
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3answers
85 views

Measure voltage difference between ground and DC floating power supply lines

110/220V AC to 12V DC switching mode power supply (metal enclosed, input is 220V with separate L,N and ground.) Measured voltage difference with a multimeter between V- and V+ 12V DC as expected ...
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3answers
255 views

Ammeter time limits - how to understand them [duplicate]

On my multimeter, near the 10 A connector it says 10 A MAX 10sec EACH 15min. I usually measure currents less than 1 A so I never cared about this. Is it correct ...
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1answer
42 views

measuring load cell output by a oscilloscope

Is it possible to read a load cell output (0~10mV with 10nV steps) by a oscilloscope? or I should buy an extra high precision Multimeter to read the load cell output?
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1answer
66 views

Would adding an LED to a multimeter's LCD screen affect readings?

I purchased a TekPower TP4000ZC multimeter, which has no backlight for the LCD. I wish to add one myself, perhaps a single led at low current, driven directly off of the two AA batteries. I'll add a ...
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5answers
1k views

Do digital multimeters require calibration?

This article Understanding Digital Multimeter DMM Specifications / Specs mention A digital multimeter will only be able to meet its specifications when it is within a certain environment. ...
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0answers
42 views

problem with dc battery source

I have a dc 9v battery which gives 8.66 volts reading when measured by a multimeter. When I connect the battery to a breadboard, without any circuitry attached within the breadboard, the reading is ...
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1answer
40 views

Metex multimeter constantly displaying overload

I have a Metex M-3650CR multimeter and have just replaced the fuse and the fuse it takes is a Fast Blow 2A 250V, now my problem is that the multimeter constantly displays OL (Overload) on the screen ...
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4answers
1k views

What's the hold function on a multimeter for?

All it does on my multimeter is freeze whatever value it was reading at the time. When would I need to use this?
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0answers
27 views

How to calibrate pico-ammeter votage bias?

I'm using Keithley 6487 pico-ammeter. It's strange when I turn on the machine without connecting any circuit, there exists 0.05 Volts difference between the in and out probe. So I have to add -0.05 ...
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4answers
362 views

Why is resistance increasing while I'm measuring using a multimeter?

I have two copper strips with a one-megaohm resistor between them. That makes the resistance between the two strips 1 M ohm. I am measuring resistance between two copper strips using a multimeter. ...
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1answer
103 views

resistance measurement problem with digital multimeter

I accidentally caused a short circuit with DMM common lead while measuring 220 AC voltage. then when I tried to measure resistance it gives me a reading of 3500 ohm while there is no resistor ...
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1answer
69 views

Need to isolate panel meters from each other?

I have a computer power supply I am planning to use for electronics work. I was planning to make a box with voltmeter/ammeter panel meters on each output voltage (3.3V, 5V, 12V, -12V). I have read ...
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2answers
86 views

voltage drop when using voltmeter

it's a theoretical question. is there any voltage drop when measuring a 12v battery with a multimeter(voltmeter mode)? so if we get 12 Volts reading near the battery, does this changes if we extends ...
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2answers
135 views

How much current does a typical multimeter draw to measure resistance?

Assuming it's running on a 9V battery like most multimeters are, and the setting is on MegaOhms. How much current will be drawn from the internal battery?
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0answers
42 views

Multimeter selection, what to look for?

I am trying to build a laser diode driver circuit which which should give a required output of around 1.25v and 200mA, I have been having problems with this and want to start inspecting it with a ...
5
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1answer
335 views

What causes inaccuracy over time on a DMM?

Here is a piece of information from a datasheet of a DMM. The accuracy rates seemed interesting for me. I wonder what causes difference in the accuracy, especially the changes after 24 hrs? Is it only ...
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2answers
288 views

How to measure current practically in a circuit

I have to measure this circuit, I have done the theoretical calculations using Kirchhoff's 2nd law, but I'm having troubles in measuring the current in each part of the circuit: I have to measure ...
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2answers
60 views

Amperage measurements using a analog multimeter

I got this $15.00 Multimeter with Amperage measurement. Do I need to put the test probes in series on the circuit? The maximum range on the multimeter is 250mA. The black probe is connected to the 10A ...
0
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1answer
165 views

Digital Multimeter to RS232 Serial Port or USB - DT830D

I am new to Electronics and doing a hobby project. I want to take some readings and get them on the computer/laptop. I am ok with both RS232 (Serial) or USB (preferred). I have a DT830D Multimeter. I ...
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3answers
127 views

Automatically measure voltage over a wide range

There are voltmeters that can measure voltage over a wide range without the need to switch the range manually. I'm quite curious how do they do it, because I'd like to make a tiny device capable of ...
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1answer
87 views

How does a multimeter sense whether it is measuring single or 3 phase voltages?

How does a multimeter sense whether the voltage we are measuring is single phase or three phase? It might be simple but I have no idea so please help me.
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2answers
464 views

Arduino clamp ammeter

I am using an Arduino Uno as a watch dog for a project I a doing; its job is to monitor what is happening in the system and shut down the system if it is not operating within spec. One of the ...
3
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2answers
201 views

Measuring current with multimeter (broken?)

I just got my first multimeter from Home Depot and it was $60. It's the Extech EX330 and it works fine except for when I measure current. I am doing it correctly and the fuse has not been blown. When ...
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1answer
47 views

Why is there a trade-off between AC current measurement and AC voltage measurement?

I am looking at buying a decent digital multimeter (not looking for recommendations), and in the products I have looked at, there is a trade-off between being able to measure \$\mu\$A and mV. eg. ...
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3answers
101 views

Determine break in long circuit

I have a circuit of switches like this. The switches are a long way from the supply and a long way from each other. ...
21
votes
7answers
3k views

How should I use a multimeter to determine which AA batteries to keep and which to toss?

I have a bag of about 50 non-rechargeable AA batteries (1.5 V) that I have collected over the years. I bought a multimeter recently and would like to know the best way to test these batteries to ...
0
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3answers
273 views

Current flow through a battery

So this might be a stupid question and I really should know the answer to it but I am having difficulties with a circuit I have made to drain a battery. The basic idea of this circuit is that I have ...
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2answers
378 views

Difference between DMM and oscilloscope measurements

I have a 220 - 14 V transformer, but when I hook it up to oscilloscope or DMM they show different values. DMM shows 11.8V and oscilloscope shows 17.2. Ok, this is cheap Chinese transformer, so it can ...
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3answers
305 views

Measuring Voltage across a resistor

I am taking my first steps into learning about electronics as a hobbyist and I am struggling to understand something about resistance. I have read about Ohm's law and it seems fairly straightforward ...
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1answer
85 views

Terminology of a “multi-meter” [closed]

I've been having this debate for a while about "what is a multi meter", and they keep saying that a multi meter is what electricians use to get voltage (see:Fluke multimeter), but I honestly believe ...
3
votes
2answers
408 views

Multimeter experiment with 10A setting — what happened?

I have a little experience with a multimeter, but I had never used the 10A setting. I was messing around with an old stereo tuner that has four fuse-type lamps used to the light the dial. They are ...
5
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3answers
396 views

Why do DMMs have so low update/refresh rates?

My DMMs ($50-$100 range) refresh the displayed value every ~250mecs. Are there technical reasons (limitations) for this, or is this just a UI thing?
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1answer
59 views

Downsides of using 5mm fuses in 6.3mm sockets

For my multimeter I need to replace a fuse. It is 6.3mm in diameter, 25mm long, rated 500mA/250V AC and 1500A interrupt rating. I have a couple of such fuses, but they are 5mm in diameter, and ...
1
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2answers
275 views

Measuring Current Consumption of USB Devices

I was trying to measure the current draw of a USB-powered device (a Raspberry Pi) to determine the suitability of powering from an external battery pack. So I took a USB cable, split the +5v (red) ...
2
votes
3answers
110 views

Accurate -2V reference

I have an old Keithley 175A multimeter that has been suffering from a bit of drift lately. Internally it uses a 6.35V zener and a couple of resistors to create a -2V reference, but the zener is ...
4
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2answers
151 views

Resistance measurement voltage - multimeters

What voltage/current is applied by modern multimeters to determine resistance?
1
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2answers
396 views

Multimeter input impedance and its effect on the measurement of charged capacitor's voltage?

while experimenting with capacitors, I charged a 15pF cap through a resistor to the voltage of a 1.5v battery. Then when I disconnected the capacitor and tried to measure its voltage with a 10Mohm ...
2
votes
1answer
129 views

Understanding current readings from a multimeter

If you couldn't guess, I'm new to electronics. So, I've just received my 3V air pump, it didn't come with any specs, so I'm trying to figure everything out. I hooked it up to a DC variable power ...
1
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4answers
96 views

Range in a multimeter

I'm an Electric Engineering student and I have my first lab tomorrow. One of the questions in the prelab asks you to give the scales and the range of each scale in your multimeter. Here's mine I ...
0
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1answer
92 views

Measuring the output of a phase control triac

I have an air compressor I'm trying to troubleshoot and I'm trying to determine if the problem is with a small circuit board with a triac. The board takes as input an ac wall outlet (US) and outputs ...
2
votes
1answer
89 views

Multimeter Manual Precision Explained

When I look some multimeter manuals it says stuff like "0,2% +5", and in videos I hear this as "0,2% plus 5 digits"...but what does it mean in practice? What is this +5 saying?
1
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1answer
120 views

DMM Auto-Polarity / Polarity detection

I have understood how auto-ranging is typically achieved on a digital multimeter, but I'm having trouble finding an example of how (DC) polarity is handled. How does the meter know if a voltage is ...
1
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1answer
166 views

Correctly measure L7805ACT regulator output

I am trying to measure the output of a L7805ACT voltage regulator (datasheet) with a multimeter, without any additional parts (no caps, etc, just the regulator). I'm using a regulated wall adapter ...