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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322 views

Multimeter, outlet and a Spark: the question of simple Voltage measurement

So I got a TekPower TP4000ZC MultiMeter. (Image source) It has COM port and two red ports: V-Ohm-etc. set at 600V Max and 500mA Max Fused 10A red fused port. Unlike other multimeters, there are no ...
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52 views

Multimeter ammeter resistance increasing

Recently I have been doing some measurements with a multimeter on some new transformers for my company. Lately I have noticed the resistance of the multimeter in current mode (ammeter) has increased. ...
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129 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 ...
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1answer
204 views

Using Voltage Regulator (9v to 5v)

I’m trying to ‘hack’ a LED Fire-effect light bulb to work on a 9v battery. Using a multimeter I can see that the bulb converts mains voltage to 5v. I’ve got my hands on a 9v-to-5v voltage regulator ...
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1answer
57 views

How to know voltage used on a data bus?

How do you find out what voltage is being used on a data bus for the high signal? On a small electronics I guess you can assume it will be 3.3v or 5v but what about other circuits, say in a car or on ...
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1answer
45 views

Discriminate MOS from BJT easily

I have a transistor for which no datasheet is available the transistor is supposed to be NPN (which implies BJT). (BD247C-Transistor-NPN, 100V 25A, 120W in TO220) how can I find out easily if it's ...
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78 views

Why does this resistor network simulate differently from the physical package?

I am trying to simulate a Bourns 4310R-R2R-104 dual terminator 104 circuit resistor network. According to the datasheet, the circuit looks like this: When I read the resistance between pin 1 and pin ...
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1answer
228 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 ...
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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 ...
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77 views

Mistakenly performed continuity test when power is on

I forgot to turn off the power of system before I did some continuity test using a multimeter. Basically an +-V dual supply was powering a transducer. Transducer was outputting very small offset like ...
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1answer
65 views

Any way to use external power for multi-meter instead of the 9V battery?

I have read discussions on NOT to use external power, say an ac adapter, instead of the 9V battery. But what if I mostly do is to test for continuity, would it be acceptable in such case? What other ...
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1answer
244 views

Why do I measure 5V in this circuit when I should measure 3.3V?

I have an audio processor board that has a 5V -> 3.3V LDO. For some very strange reason, when I measure the voltage of the output of the LDO, I read 5 instead of 3.3V -- which by the way is a lethal ...
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2answers
163 views

My multimeter probes are too big to measure a laptop battery

I'm having laptop battery problems, and the hardware manual gave diagnostic instructions involving measuring the voltage in the battery. So I bought a multimeter (never used one before in my life) and ...
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3answers
148 views

Can you determine RGB pinouts with a multi meter?

I have a Swiftech Apogee XL2 that has an addressable LED inside it. I want to connect it to my other RGB setups but I need to know the pin signals and voltage of the LED. I have a multi-meter at the ...
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2answers
976 views

Multimeter true RMS [closed]

I'm just getting started with electronics (arduinos and friends) and I would like to get a multimeter. As far as I can tell arduinos and any other logic chips and circuits I'm gonna be using are using ...
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1answer
57 views

Multimeter temperature coefficient - Specified accuracy

I want to calculate the temperature coefficient for a digital multimeter. The datasheet I read it is calculated as: 0.1*(specified accuracy)/°C (<18°C or >28°C) Do you know what specified ...
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2answers
1k views

Test a transistor with a multimeter

I used the guide at https://vetco.net/blog/test-a-transistor-with-a-multimeter/2017-05-04-12-25-37-07 to test a transistor with my DMM. The NPN transistor I used to test is the "mospec tip130 No11D" ...
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2answers
498 views

True value of skin resistance

When I googled about skin resistance I find people mentioning values as low as 500ohm but usually around 10-100kohm. When i measured the resistance of my own skin by putting the probes on the inner ...
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2answers
99 views

Please Critique my HV Measuring Setup

At the moment, I am working on a device that will be able to measure the out put of a high voltage DC power source with an adjustable output of 0 - -60 kVDC and 0-15 mA (the typical power being 600 ...
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3answers
710 views

High Voltage Measuring System

I am looking to set up a voltage-measuring system for the output of a recently purchased HV power source. The source supplies around 0 - -60 kV DC and 10 mA to my load. Unfortunately, the source does ...
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3answers
235 views

Tool for Measuring Low Current

I currently have a power supply that will be able to supply around -60 kV DC and 10 mA under the load that I will be hooking up to it. However, the internal resistance of the load will fluctuate and ...
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1answer
138 views

Did I ruin my multimeter with a current measurement?

I am trying to do a current measurement. Probably I accidentally put it it parallel instead of in series. What I tried before/after that (cannot remember exactly putting it parallel but might have ...
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126 views

Getting Rid of Annoying Buzzing Sound from Multimeter

my multimeter has been bugging me with this buzzing sound that turns on and off while I'm using it. I think it has something to do with its autoranging feature, but I couldn't find the manual for this ...
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3answers
97 views

How to know when to tune up a digital multimeter?

I have bought the multimeter with temperature measurement from the following website: http://futurlec.com/Multimeters.shtml Currently I use the voltage, resistance, and short circuit detection ...
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1answer
295 views

How to add a LED to a Multimeter for use it with the buzzer in continuity testing?

I want to add a notification LED to my digital multimeter which i need to glow with the multimeter`s inbuilt speaker (piezo/buzzer/beeper) while in Continuity testing mode. MM Model : DT830D If i ...
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1answer
2k views

Multimeter shows OL or 0.00 or 1.00. What's wrong?

I've got a UNI-T UT33D multimeter that's not working like I want it to, and I'm not sure how to find out what's wrong or if it's salvageable or not. The unit is new, but may possibly have had its ...
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1answer
307 views

How to test 3528 smd LED

Using my DMM and the diode selector, the SMDs 3528 in a brand new Led bulb does not light. I used this method to test the classic "round" leds but in this case it does not work. What seems to be wrong ...
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1answer
97 views

Am I using my multimeter correctly to measure current?

I've wired up a simple circuit using: 9V Battery Blue LED 220 Ohm Resistor I was expecting a much higher value of mA? Is it true it's only 0.8mA? Shouldn't the LED light up, since we're closing the ...
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1answer
73 views

Is it possible to “intercept” a 20-pin FFC?

I'm not an electrical engineer but a software developer but I'm trying my hand at a DIY project that will involve connecting a couple of pins on a device in my home to the GPIO pins of a Raspberry Pi, ...
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1answer
87 views

Ammeter for 24V power that can be read by a Raspberry Pi?

I have a project I'm trying to design and build that involves a "more accurate/useful" battery gauge for an electric scooter. The scooter runs on 24V off of two AGM cells in series. The details of the ...
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1answer
95 views

Measuring 200 volts safely

While I can measure line voltage safely, I need to write a procedure to have someone else measure the voltage. The load is pure resistive,and I want to measure the voltage across it, with a battery ...
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1answer
75 views

Measured amperage differs greatly from my math

I've got the following circuit: simulate this circuit – Schematic created using CircuitLab It works. The LED glows nice and bright. However my math doesn't match the readings I'm getting from ...
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2answers
188 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 (...
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1answer
3k views

Using a multimeter, can I tell if a lithium-ion battery pack is brand-new?

A few years ago, I ordered a replacement cell phone battery from Amazon, and while it worked, it didn't last as long as I expected. I wondered if the seller had scammed me by selling me a battery that ...
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4answers
148 views

What is the recommended battery chemistry for digital multimeters?

I would like to know if the different internal resistances of different battery chemistry somehow affects the calibration of a digital multi-meter. If so, then what would the optimal battery ...
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2answers
2k views

Manually test computer Ethernet port with a multimeter

I have updated the drivers for the ethernet port an a laptop at home, yet it is only letting 10 mbps through for every cable that is connected, even though Speed/Duplex was set to Dual 1 Gb. I now ...
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106 views

Logic analyzer not shown signal

Good day. I am trying measure signal on ISO 9141 K-line - bidirectional serial link using logic analyzer. The device is Atmega based device with L9637 K-line driver chip. Problem is that, no signal ...
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5answers
386 views

Measuring Current Using A Resistor?

Sometimes in videos made by the YouTube creator ElectroBOOM the creator says he is using a 1 ohm series resistor to measure current. I looked it up and found some links to forums where people are ...
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78 views

Understanding the resistance readings between PCB connectors

Based on a question I asked earlier today, I am trying to verify that there's not short caused by my bad soldering. Luckily I had bought two of these modules. To make a baseline, I started looking ...
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31 views

Waveform monitoring on PC

I'm searching for a simple multimeter / oscilloscope simulation on Windows/Linux, which has the ability to import txt. or csv. datafiles and generate a video of an alternating voltage. I've been ...
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1answer
130 views

How do multimeters measure capacitance of polarized capacitors?

On my multimeter it doesnt matter in which polarity I put polarized capacitor. How is it made? If it is just simple rc circuit that measures charging time, how does it not damage capacitor in ...
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2answers
112 views

Using a lower voltage for a replacement fuse

I need to replace a blown fuse in my Tacklife DM02A multimeter. It says on the back of the multimeter that the blown fuse is F1 250mA 600VAC. Its size is 5mm x 20mm and it has to fit into a clip ...
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1answer
165 views

Is my multimeter broken?

First, let me say that I'm very new to electronics so this issue may just be down to me doing something wrong. Here is my multimeter: It started when I was trying to test the gain of a PNP ...
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3answers
692 views

Can some clamp meters measure voltage through their clamp?

A simple question, is it possible any clamp meters to provide voltage readings when a cable is between their clamp? I see from specifications for meters that they don't seem to do that and instead ...
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2answers
28 views

Figuring out if an led strip/matrix has a short or not with a multimeter

I am relatively new to electrical work, mostly stay on the software side of things. I recently soldered header pins onto a few led matrixes I have. They are 3 wire leds (power, data, ground). I'm ...
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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 ...
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117 views

Why do I read resistance on the continuity setting but not on the resistance setting?

Disclaimer: Newbe A multimeter tutorial on Youtube said that to test my washing machine inlet valve solenoid for continuity I can use either the lowest ohms setting (200 on my DT830B) or the ...
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4answers
1k views

Is there any advantage to have a dedicated hole to measure milliamperes on a multimeter?

I have noticed that high-end multimeters usually have four holes: Common (COM) Volts (V) Milliamperes (mA) Amperes (A) While cheaper ones usually have three holes only: Common (COM) Volts (V) / ...
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58 views

Continuity Testing

I have a fluke 381 and i was talking to another tech about testing voltage sensing fuses in a live Automatic Transfer Switch, the fuses are 2 Amp HRC type fuses and i made the comment that i have in ...
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2answers
71 views

How to measure resistance with a multimeter?

This may be a very simple question. In my lab guide (I am a freshman Electronic Engineering student), we are supposed to build and analyze a circuit on a breadboard. First, we need to select some ...