Questions tagged [multimeter]

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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46 views

Repairing a multimeter

I am attempting to repair my multimeter which hasn't worked since I tried to take an AC reading of an electrical item that blew a fuse and caused a loud pop on the source. Since this even the lcd ...
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Why does my voltage divider output seem to vary depending on the order of magnitude of overall resistance?

I'm working on a project where I want an Arduino Uno to measure the voltage of a 12V lead acid battery. The Uno's analogue read pins can't handle raw 12V, so I need to use a voltage divider with ...
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51 views

Using a cap to predict the presence of a pulse via voltmeter

I have a pulsed power supply that provides 250v pulses with a pulse width of 2 uS and a frequency of 10 Hz. However, I'm unaware of the polarity of these pulses. In order to detect the polarity of ...
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What does the horizontal bar indicate in the DMM display?

What does the horizontal bar indicate and how to use it in my measurement?
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Multimeter can't measure current. Maybe broken?

So basically when I put red jack to 10A mode it shows amperage fine, but when I switch to other, it shows 00.0 eveywhere, even when I set to micro amperage it doesn't react to my tongue and skin. It ...
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Multimeter capacitance value - ADC readings

I have set up my raspberry pi to read from the MAX1204. To know if I'm reading the proper value, I use a multimeter at the input channel of the ADC, and compare it to what I read through my program. ...
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5answers
257 views

Choosing a digital oscilloscope for a self learner [closed]

I'm about to start a course about electronic interfaces. My intention is to learn to debug hardware by doing measurements etc. with oscilloscopes and multimeters. According to the course, the ...
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177 views

Is there a difference between measuring the resistance using a multimeter ohm function and using the voltage / current relation?

I need to measure the electrical resistivity of a concrete sample following the procedure described in ASTM C-1760. The procedure requires a 60V DC potential to be applied across the concrete sample ...
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5V LDO blowing up only when testing current draw

I have a circuit to power some 5-volt logic from a +24VDC source. It has some basic reverse-polarity protection and uses a TI 5VDC LDO. It all works great during normal operation however, when I use ...
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Why did my meter read 6 volts dc in the speaker output of a car radio?

While probing a "live" car stereo pins, I also probed the speaker output pins but left the meter in dc volts mode and got a reading of 6v, wich I think is odd, as I asume the output should be ...
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Schottky diode / Rectifier Diode difference and how to test them?

I have 3 diodes that I would like to test 1x USD935 2x USD2009 USD935 is identified by its datasheets as a "Power Schottky Rectifier Diode". I cannot find the datasheet of the USD2009 but they have ...
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62 views

How can I identify a diode without a circuit diagram?

I have a multimeter which I have been given. It belonged to a friend whom has passed away. However I have found that it isn't working properly. Upon inspection, I have found that 2 diodes have shorted,...
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What Multimeter reading?

I´m doing a parasitic draw test on my car battery, in order to check the draw with the car locked and alarmed I need to use the COM and 20a sockets of the Multimeter, if I use the COM and mA sockets ...
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Multimeter Always Reads 60Hz Measuring a CD4060 Pierce Oscillator

Using a CD4060 IC I’ve built a crystal oscillator circuit similar to the one in the image. I’m trying to use my klein mm400 multimeter to measure the oscillation frequency so I can get a rough ...
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44 views

Multimeter is showing wrong resistance [closed]

I accidentally pluged my multimeter in a 220 v 50hz power supply keeping the knob on the resistance section. Now when I rotate the knob to the resistance part it always shows 24 ohms although there is ...
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Auto Scaling in a Multimeter

I’m trying to create a multimeter, I’ll be mainly using a 16 bit ADC (ADS1115), an ESP8266 on Node MCU, I’ll use the MCU to communicate with a phone app to switch between different multimeter modes, i....
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Current from thermocouple (T/C)

Studying thermocouples (T/C), I have a question regarding the output. Generally speaking, in the case of T/C, we measure the thermoelectric voltage in millivolts. Why do we calculate not current, but ...
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3.3M resistors not registering on multimeter - are they faulty?

Please keep in mind this is my very first electronics project so it’s entirely possible I’m doing something wrong. Here’s the deal: I’m building a contact microphone from a kit that came with four ...
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37 views

Multi-Conductor DC Clamp Meter

Does a multi-conductor DC clamp meter exist? Possibly using hall effect sensors in a specific orientation? I typically work with 24-28V DC solenoids valves & pressure transducers with 2 and 4-...
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70 views

What does this notation do in multi-meter? [closed]

What does this red marked area do in this multimeter? UT33B Palm-Size Multimeter Model: TOL-00032
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1answer
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Can capacitors be damaged by a DMM in continuity mode?

Some multimeters have a pretty high open circuit voltage in continuity test mode and resistance mode (possibly to improve SNR?), but they are current limited. For example, the Fluke 87V behave like an ...
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How to find current and voltage of a certain appliance connected to an outlet?

Objective: I'm new to electricity and trying to convert my mirror integrated with LED work with a power bank. I need to find how much voltage and current is needed to make it work. How can I measure ...
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How to find the short circuit element on electronic board easily

I have two Uster Tester ( this machine used at textile) cards. one is corrupted and the other is the same one that works. Trying to repair the corrupted card by performing comparison test. When I try ...
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103 views

Digital multimeter

When we measure an electrical quantity on Digital multimeter (DMM) like current, if we dont get readings of small range scale we switch the range utill we get our reading, same goes for voltage. But ...
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1answer
108 views

Do these multimeter readings even make sense?

I'm measuring resistor values and I believe I've set the multimeter correctly. I verified some pre-known values. Measuring this one resistor, I get 3.0 on the 200M scale and 0.03 on the 20M scale and ...
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77 views

Current and resistance

Can anybody explain why my tongue gets a reading on a multimeter. Do I have a current? Why do i have resistance? Why do some things have resistance? I am very confused.
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Determine possible thermistor value in multimeter

I have a Toptronic T835 multimeter that has a cracked component that looks like a thermistor. It is marked TR1 on the PCB. The only text on the component is first row [obscured character]B and second ...
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HV probe to CRT oscilloscope?

Can you guys tell me if it's okay to hook up my HV prove to my CRT oscilloscopes? And what about a multimeter, what kind of precautions do I need to take with using that? I read somewhere that it's ...
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2k views

Why doesn't my multimeter show the correct Zener reverse voltage?

I have a 3.3V Zener diode, brand new from a reputable source. When I set my Fluke 101 multimeter to diode test mode, and put the black lead next to the dark bar on the diode and red on opposite side, ...
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79 views

Measure 220V alternating current with a multimeter in DC mode

What happens if we measure 220V AC from wall socket with a multimeter in DC mode (instead of AC)? If I remember correctly, it should show the average value of this sinusoidal 220V, i.e. 0V. Is ...
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43 views

Reading of megohm during ground check

During the check of pins on connector with a multi-meter, one of the pins that goes through the relay to provide ground signal, I am getting 8MOhm (8 megohm). I should not be getting anything on that ...
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74 views

Circuit Representation of an Unknown Switching Transformer (Including Dot Notation)

Is there a way to identify the phase of the transformer's coils without having to see its waveform in an oscilloscope? For example, I have this unknown switching transformer The only thing I know is ...
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41 views

How to find out the maximum current across a voltage source(using a DMM)?

I have an old Nokia phone charger lying around which I want to adapt for powering my breadboard/PCBs. I was trying to find out how much current the charger was able to supply, so I connected a DMM ...
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58 views

Is it harder for a low-battery DMM to measure current in a comparison to measuring voltage and resistance?

My DMM is doing a good job in measuring voltage and resistance but when I measure currents I get 0 readings. Is it possible that having a weaker battery affects only current measurements/ If so - why?
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199 views

How to read the position of the decimal point with this multimeter?

Note (edit): This cheap multimeter has a bad serigraphy, confirmed by comments of other buyers. The top range should probably be 200 µA. I rarely use my multimeter in current mode (I usually it in ...
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2answers
254 views

Digital Multimeter “Continuity test” only one single beep

Well I have two electronic circuit, one is broken and the other is solid and working. While I am making Continuity test with Fluke Multimeter on working electronic circuit, the bip voice heared only ...
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1answer
81 views

When checking for continuity between two points on a PCB, how do I know it's not going through an inductor?

When trying to debug a non-working circuit on a PCB, it can be difficult to trace the circuit flow visually, as described in the answer to this excellent and related question: How can I reverse ...
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I am measuring a 9W LED with a clamp on ammeter. Why does it only draw 7.62W?

I bought a UNI T UT210E true rms multimeter. I measured the current of 9 W LED lamp. It shows 0.033A. For the power I get \$0.033 A \cdot 220 V = 7.26 W\$ only. ...
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224 views

What informations can we obtain with these voltage and current measurements of a little electronic device?

I powered a little electronic device with 2 AA batteries and here are the results measured with a multimeter: When using a first set of 2 AA batteries: Voltage when device unplugged: 2.45 V Voltage ...
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Booting up a Lomvum T28B multimeter!

I have the above mentioned multimeter; I know this seems trivial but I'm new to this how in the world do I switch it on. There is no indication in its manual of where the power button is. Am I missing ...
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407 views

Why does the measured current differ from the calculated current in this circuit?

I have the following schematic: Now I want to know the (more or less) exact current flow in my circuit. For this I did the following calculations: I = V / R I = 5V / 330 Ohm I = 0.015A = 15mA So ...
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85 views

Will multimeter show a voltage in an electric field?

I think that it won’t because there is no current entering the meter with which it can measure. Correct? Also, is it the same reason why the meter won’t show a reading even though one probe is in air ...
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How to insulate more of my fluke test leads [closed]

these are the test leads I own, I am wondering if there is a something I can purchase to shield the exposed metal more to avoid incidents. I heave the little plastic shield that comes with them but ...
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100 views

How much current does this read?

How much current is flowing here?
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How can you damage DMM if you haven't discharged a capacitor?

Hi, I measured capacitance on some capacitors using my UNI-T 139S True RMS Multimeter without discharging them first. To be clear, I don't even know if they were charged because they are mounted on ...
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2answers
60 views

Reading voltage from coil on top of Qi Wireless Charger

I am a high school student doing a lab report on changing the number of turns of a coil and seeing the effect it has on the output voltage from a wireless charger. I am trying to take a Qi Wireless ...
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106 views

Can I make a ammeter using a voltmeter and ohmmeter that would work in parallel to the device?

I had this small question today when working with an ammeter. Since an ammeter must be in series of the circuit, I had to constantly break the circuit to take current readings. Whereas, when using the ...
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631 views

How do we test and determine if a USB cable+connector is version 2, 3.0 or 3.1?

How do we test and determine if a USB cable+connector is version 2, 3.0 or 3.1, without using port, PC and/or having data transfer but instead with basic physics tests e.g. using multimeter?
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Two different LED types: diode test on two different multimeters shows just “1”

I have two multimeters - granted, they're both the super cheap DT830B types, but slightly different models and one is straight from the packaging. I also have two bags of LEDs - bright red and bright ...
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52 views

How could I measure RF transmission power from SMA connector without having a RF wattmeter equipment?

I need to measure the RF power of a radio transreceiver, and since I haven't specific RF wattmeter equipment, I'm wondering how I could do this using a classic multimeter. I would avoid to ...

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