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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.

-2
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0answers
703 views

STPM34TR multimeter IC

Hello I am working on a project that requires utility grade metering, and so we using the STPM34TR. The hardware is working and we have looked over the datasheets, the internet and anything else we ...
16
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2answers
2k views

Determine voltage drop over 10G resistors with cheap multimeter

I have two 10G resistors connected in series with a 3V battery. I want to determine the voltage drop across one of them, which of course is 1.5V. When I use my multimeter to check the voltage drop, it ...
0
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1answer
55 views

Measure voltage of the panel light bulb inside a vintage radio

I'm new to Electronics. I have recently received a vintage radio Pioneer TR-305. I am trying to replace the panel light bulb inside this radio. I opened the radio panel and found the bulb soldered ...
0
votes
2answers
111 views

Multimeter “false” measurement in car

Given my mom's car, I measured a voltage in an electric connector equal to the voltage across the car's battery. This is when the multimeter is connected to the connector supply pins. If I take the ...
0
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1answer
47 views

Wheatstone Bridge - strain gauge sensor

I'm trying to optimize a Wheatstone bridge with a strain gauge sensor and I'm considering all possible wire resistances. The circuit is shown in the following figure: I don't understand the comment ...
7
votes
5answers
16k views

Why does a multimeter show VAC on VDC power supply output?

I used my simple digital multimeter to measure the real output of several small PSU's I have got at home. They all should give just direct current and show some values in VDC mode, but the multimeter ...
0
votes
1answer
103 views

Current decrease in a lamp due to the change in scale of an analog ammeter

I do not understand what happens in the following situation regarding internal resistance of an analog ammeter. The internal resistance of analog ammeter changes if the scale is changed. For example ...
3
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2answers
59k views

How to check earthing using handheld digital multimeter?

I would like to know to how to check for earthing (electrical) ina house using handheld DMM.
0
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2answers
55 views

How to use a multimeter to test the resistance of my tongue?

I just purchased this cheap-o multimeter: https://www.amazon.com/AstroAI-Digital-Multimeter-Voltage-Tester/dp/B01ISAMUA6/ref=sr_1_1?keywords=astroai+am33d&qid=1551837071&s=gateway&sr=8-1 ...
0
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1answer
96 views

Negative and positive electrodes on a battery - confusing results

We created a voltaic pile battery and tested voltage with a multimeter. Each cell is comprised of a penny and a nickel with wet paper in between (vinegar + salt solution). Then you simply connect ...
51
votes
7answers
103k 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 ...
8
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2answers
29k views

What color is positive on a multimeter?

I bought a multimeter with attached leads. I would think red is positive but when I take a reading it only works if I use black as positive. Was it assembled wrong? There's nothing in the manual. It's ...
5
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3answers
16k 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 ...
0
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0answers
22 views

Monitoring and data logging [on hold]

I'm still very fresh into electronics and circuits so I havnt learned all there is to know as of this moment and at the rate technology advances I doubt I ever will, mayby I'll get close one day. ...
0
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1answer
105 views

Ground loop current for voltmeter

I am trying to build a voltmeter, but the voltmeter is powered by a 12V dc adapter. My concern is if the ground potentials between the analog input source and the voltmeter are different (e.g. due to ...
-3
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1answer
66 views

Multimeter Giving Wrong Temperature Probe Readings [closed]

I want to ask a question about my multimeter, it's new but when i plug in the temperature cable - red to VOhm, black to COM and turn to tempreture it displays temp of period(-886°C/-900°C), and when i ...
1
vote
2answers
123 views

Measuring wattage to PoE device - how to hook up a multimeter inline?

I'd like to measure the amount of power drawn by a PoE client device (PD) and would like to hook up a multimeter inline to do so. However, power is supplied to the PoE device over two pairs of wires (...
0
votes
1answer
54 views

Circuit Failure How to fix it? [closed]

I'm sorry I am very specific here, I have a problem with the charger of my motorbike dashcam and I hope you can help me fixing it (see picture and video test with multimeter). I really have no idea ...
0
votes
2answers
117 views

Why do different resistors of the same power rating burn out / not burn out?

I have a circuit board for a small LED light, which comes with an annoying strobe mode. To disable this I have found that I can wire a resistor from a pin on a chip to ground and the LED will stay in ...
0
votes
1answer
75 views

Display input from multimeter on PC

I have opened a Multimeter (Model:DT830D) and I want to take the input that is fed to the LCD display and display it on my PC instead using the serial monitor of the arduino. But I am confused about ...
0
votes
3answers
106 views

multimeter temperature accuracy [duplicate]

I have tried searching for an answer and looked online, but I'm just getting more confused. I have a DMM that measures temperature with a thermocouple lead, with a resolution of 1 degree C (shows 020)...
2
votes
1answer
168 views

How to test transistor with Built-In Biasing Resistors

On a GPS device pcb, I found a small smd component that is marked as "22p V2". I found (tell me if I am wrong here) that it is a transistor like DDTA144WCA-7-F SOT-23-3 package, with built in biasing ...
0
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3answers
87 views

How to read a multimeter (digital) — should I get 2A readings from a couple of AA batteries?

I have been using some old multimeters in a high school science lab. We did a current an voltage reading from a AA supply (two batteries) with a variety of resistors. In some cases a 1M resistor. I ...
0
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1answer
767 views

Voltage sensing using Arduino with and without common reference

I wish to make a voltage sensing circuit (range -15V to +15V) using an Arduino's ADC. The problem is that since this circuit will be part of a much larger circuit in which the Arduino is performing ...
0
votes
1answer
175 views

Why can't I use lithium batteries in this multimeter?

I have essentially the same question as this. In that question, it seems lithium batteries are prohibited for use in the device because it wouldn't adequately warn the user that the batteries need to ...
0
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2answers
39 views

measuring resistance on hv transformer

I need to verify the resistance on a HV transformer that receives 208v single phase through terminal 1 and 2, or 240v through terminal 1 and 3 and delivers 4000v through terminal 4. As per the ...
5
votes
3answers
1k views

Why can't I get a resistance reading on my temperature probe?

I'm a complete beginner to electrical engineering, so I think I might be doing something stupid here. I have a set of grill temperature probes I ordered from Amazon. I am trying to find out the ...
0
votes
2answers
103 views

Testing crystal oscillator with multimeter crashes system

I have an old XT computer with a crystal oscillator that I would like to test. My multimeter has a Mhz setting that as far as I know should allow me to test it. (Providing the crystal is powered) ...
13
votes
9answers
3k views

In which scenarios is it important to measure microampere?

With the situation of finding a new multimeter, I found myself lost to the number of available devices on the market. For sure, to find the most suitable device I have to set some requirements. While ...
4
votes
2answers
174 views

Good equipments to measure current consumption for IoT devices

I was asked to bought some equipment to measure the current consumption for the IoT devices. The company is a startup and has a limited budget for this (let's say less than 5k$). I'm looking for an ...
13
votes
5answers
44k views

What is the difference between a multimeter with RMS and one with True RMS?

I am looking for multimeters. I am only a beginner in electronics, but I want to buy one that will be good enough for me for a while. I found a multimeter that measures True RMS, and another one that ...
0
votes
2answers
5k views

How to test the voltage of a speed sensor and identify the +ve, ground and signal wires using a DMM?

I am a novice and would like to identify each of the wires going to a speed sensor. Below is a photo of the connector from the mainboard (left) to the sensor (right): Is it possible to identify ...
3
votes
2answers
585 views

Why do some multimeters have discrete ranges for measurable values and some just measure based on signal type?

I have a multimeter in my toolbox that has ranges of values it measures in dc voltage, a lot like the one below which can read DC but reads it by orders of magnitude. In order to get a proper reading ...
1
vote
2answers
99 views

Is this transformer working?

I found this transformer and I am not sure if it is working. I am confused with the multimeter readings. For example: when I am using the buzzer option to check the connectivity it buzzes when I ...
0
votes
1answer
167 views

Meter fuse availability/substitution conundrum

I own a Brymen BM235 multimeter, among other test instruments. While it's a nice multimeter, I have one problem with it: the fuse for the mA jack is a Siba 7017240.0,4, and nobody even bothers with ...
0
votes
1answer
76 views

Seared my circuit while checking voltage [closed]

I was attempting to diagnose a problem with my dvd player as I was not getting any power, I wanted to use my multi-meter to see where the circuit was shorting out, I set the setting on the multi-meter ...
5
votes
4answers
1k views

Why do LCR meter manufacturers give the details of measurement frequency to us?

When you want to purchase a DMM, more probably you don't see at what frequency the DMM you considered would work, but in the situation you're considering to purchase an LCR meter, manufacturers give ...
0
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1answer
57 views

Measuring USB power adapter quality using multimeter

I have heard horror stories about poor quality USB power adapter. I have a collection of no less than 20 USB power adapters, most are from cell phone manufacturers and some from small projects. I ...
5
votes
3answers
19k views

9V battery and resistor are connected in series - the voltage across the resistor is < 9V. Why?

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 ...
1
vote
1answer
3k views

Microphone voltage output - is it AC?

Can anyone tell me if the output voltage of a microphone (like the type on a webcam) is an AC voltage? And whatever it is, can it be measured on a standard voltmeter? Thank you.
0
votes
1answer
51 views

Continuity testing - Why does swapping DMM probes give differing results?

Continuity query - Can anyone explain this? Circuit is a simple 12v DC, wired as follows -battery pos to bulb to spst switch back to battery earth. Testing with DMM in the dedicated audible ...
0
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0answers
79 views

Darlington Transistor TIP142 same type but different values

I have a bunch of Darlington NPN Transistors TIP142 that are removed from two separate identical boards. The 1st one have the TO−218 CASE (left side of the image) and the 2nd the TO−247 CASE (right ...
0
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2answers
56 views

CB blew when trying to measure the current using multi meter. What went wrong?

I set my multimeter like this. Plug the black lead to the short tab of NEMA5-15 receptacle first and the red lead to the long tab. The moment I put the red lead in, there was a big spark. The ...
0
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2answers
221 views

DC current consumption with sense resistor, different measure on oscilloscope and multimeter

I'm doing low side current measurement over a 0.1ohm resistance. Load is a DC motor powered with 12V. Cable length between resitor and power supply ground ~60cm I get a voltage of : 75mV => 750mA ...
1
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2answers
119 views

Can I use any HV Probe for a Voltmeter/Ampmeter gauge?

I purchased the multimeter pictured below for a high voltage power supply I'm working on. It's rated for 100V DC and 10A, but I hope to measure several thousand volts. Is it possible to use a HV ...
0
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3answers
98 views

how to avoid brownout caused by a multimeter on esp32

I am using the VOLTCRAFT VC130 multimeter for measurement of current through my esp32. The microcontroller runs perfectly with two 1.5V batteries(~3V as read by multimeter in voltage mode). But when I ...
1
vote
3answers
102 views

What is line to line voltage supposed to meter at?

I'm pretty new to this but I know that in three phase power, when I'm metering line to line its usually at 208V, but I've been told that line to line meters at 240V. I don't know what would cause for ...
7
votes
3answers
812 views

Is a multimeter with 1,200,000 counts actually a 6½ digit multimeter?

The Keysight 34465A Digital Multimeter is specified as a 6½ digit multimeter. However, the meter is actually a 1,200,000 counts meter, since the meter wraps at 1.2, so if measuring a 1.19 kOhm ...
1
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1answer
63 views

How can I make my measurements of full-wave rectified AC using an A/D match a Fluke meter on its DC range?

I am trying to measure the DC voltage of a full-wave rectified 60Hz AC signal using an A/D and have it match what a Fluke meter reads on its DC scale. My current approach is to take as many (16 bit) ...
0
votes
3answers
493 views

How to check continuity or shorting using arduino

I was trying to build a multimeter using an arduino (just for learning purpose). I am able to measure voltages directly using analogRead() and for measuring currents I am using a o.o1ohm shunt ...