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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43 views

Do I need to replace removed parts with a resistor? [closed]

I have some external hdd-drives. Their cases usually have a led and sometimes a fan. If I want to remove e.g. the led or the fan, do I need to replace them with a resistor? I am aware that removing a ...
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Probing With Multimeter Breaks LED - Happened Twice

Qucik background info: I am using a 117 Fluke, brand new bought in 2020 from Amazon. What happened/happens: This is a very simple circuit, but for some reason the resistor keeps heating when I try to ...
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mimicking DVM 10 to 11MΩ input impedance on microcontroller analogue input

I'd like to mimic a digital volt meter's high input impedance (10 to 11MΩ) at an analogue input (ADC) on a microcontroller. Currently I'm using an ATmega32U4-based Kookye Pro Micro. Specifically, I'...
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how to calibrate my multimeter temperature probe

I have a multimeter with the following temperature accuracy for its Type K probe ±3% of reading ±5C The display is in steps of 1C I attempted some calibration: In ...
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How does a multi-meter diode check work and how to test an RF diode with it?

This is a followup question for Can I debug this simple circuit without VNA and proper RF equipment? which I am still fighting. The diode as a nonlinear element could explain all the weird behavior I ...
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Measuring back EMF induced current with multimeter

I have built a solenoid with copper. It is 19 cm long, it has 64 turns and the radius is 1.5 cm. To trigger back EMF, I use a permanent magnet that has the same surface as the cross sectional area of ...
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38 views

Voltage difference on DSO-150 'scope' and Fluke 87 multimeter

I am attempting to use a ESP32 to make a Yamaha Receiver internet connected through the receiver's cabled connection to pass remote button presses. I have found a manual detailing the protocol and ...
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64 views

Measuring Diode “Pushback” Voltage

I was recently learning about how a diode works, and I understand how a diode, in it's natural state, develops a sort of "pushback" voltage that pushes against any voltage that is applied, ...
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How to test a half wave bridge with a multimeter

I found a box of LAS-8500P half wave bridge interface drivers in my attic. How can I test them with a multimeter to see if they are any good? Data sheet https://datasheetspdf.com/pdf-file/531203/...
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I fried my Fluke DMM while measuring voltage across a BBQ Piezo spark igniter. How to fix? [closed]

I was trying to figure out how I broke my Fluke (and more importantly, how to fix it). I had a grill spark generator (such as pictured below). It wasn't working correctly, so I was measuring (I think) ...
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Is one of my multimeters wrong?

I have a Panasonic PIR sensor (EKMC1603111) and am measuring the voltage between the output pin and ground pin. On the green multimeter I read 0v when there is no motion and 3.3v when there is motion ...
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Can multimeter measure 3200µF if capacitance measuring range:10p…40n/400n/4µ/40µ/200µF?

A multimeter that has this specifications: Capacitance measuring range:10p...40n/400n/4µ/40µ/200µF will not be able to measure a 300µF or 3200µF capacitor? That's how it sounds, but I want to make ...
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How can I make this Component Tester more accurate?

EDIT: In the answer by Reroute (thank you, Reroute!), he references a very active 253 page EEVblog topic -- $20 LCR ESR Transistor checker project that probably includes exactly what I am seeking. I ...
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Calibrate multimeter VC9205A

I have a multimeter type VC9205S. I plugged it in to power 9 volts because the battery is empty. Hours later, negative readout values ​​began to appear. 1- Can the device be calibrated or not ...
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Why would bridging a varistor with the multimeter leads on any setting have caused the unit to turn on?

So I've been working on fixing this window AC unit for a while, and when I started I knew next to nothing about circuits. At present today, I know a bit about circuits -- enough that i at least know ...
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Reducing errors in 3-wire PT100 RTD measurement using a Keysight 34461A DMM

I have a 3-wire PT100 RTD with 1.5 m long cables, which I want to measure with a Keysight 34461A DMM. This DMM has a temperature measurement mode for use with RTDs. Aside from bundled probes, I have ...
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51 views

Measure resistance of resistor in cirucit

How do I measure accurately with a multimeter the resistance of a resistor that is already soldered as part of a circuit? In a simple transistor as a switch circuit, I noticed that when I tried to ...
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My Mastech MY-64 DMM shows incorrect voltage for specific selected option

My Mastech MY-64 DMM suddenly started showing incorrect voltage on DC 20v option only. When I select dc 200 option it show correct value, even a aaa battery in 2v dc option show correct voltage. Why ...
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How to detect if a TRS cable is connected to a MP3 player output?

Imagine I have a MP3 player and one male-to-male TRS cable that could be connected or not to ...
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356 views

Can continuity test cause component damage?

In order to test some tracks on a mounted PCB, I would like to use a multimeter for continuity test. However, then I measured the open-circuit voltage of two multimeters at hand, and the results were:...
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What is 1.5%rdg + 4dgt for 15,23 V?

Where "Rdg"is for reading and "dgt"is for digits. So, 15,23 * 0,015 = 0,22845. Rounding to most significant digit it's 0,2. So is this correct? $$15,23 \pm 0,2$$ Since 4dgt is smaller we ignore it. ...
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Fried microcontroller while taking a voltage measurement?

Alright, feeling pretty dumb here lol. I was taking a DC voltage measurement with a Fluke 87 V from a pin of a microcontroller to GND, when out came the magic smoke. The pin I was measuring is a 5V ...
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54 views

Using a slider potentiometer with an Arduino

I'm new to electronics and in the process of building a Joystick using an Arduino Leonardo. I am reusing parts from an old Joystick from the 90s https://www.amazon.com/F-15E-HAWK-Tactical-Control-...
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What does it mean when a battery still has high voltage but doesn't deliver current?

All the dead batteries I tested had very small voltage and no current under load except one strange battery that had about 2 volts but no current. What causes this different type of dead battery?
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Finding each UART pin with multimeter

I am trying to findout the pinout for Serial Connection to a router. However I wasn't able differentiate the pins other than GND. Pinout: ...
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32 views

Test “wall wart” power supply

I am purchasing a 3 ampere USB A power supply (5V.) What would be the easiest way to apply a known load from 0-3 amperes (in 0.5 ampere increments, for example) so that I could connect a multimeter ...
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55 views

How to check the power output of home amplifier speaker terminals?

I recently bought a Sony STR-DH800 from eBay and to cut a long story short I'm getting different volume levels using the same speakers across the various speaker terminals. I have a multimeter and I ...
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31 views

Checking amps with manual-ranging meter: Jack/dial consistency required?

Multimeter: UNI-T 89XD manual ranging I received a comment or two that said I will not get an accurate amp reading if I use the 20 amp jack and set the dial to anything other than the 20 amp setting,...
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Getting to know why my meter does what it does: 11 volt LED tester question

While all your great answers to my previous question are simmering in my brain (I printed out all your answers and placed a copy on my work bench to have another go at it), I have one more: As I ...
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48 views

ic to range ADC inputs

I'm trying to figure out how to implement an auto range by changing the resistors values for R2 and R3 with a MCU. First I was thinking of using a mux like the ADG5208BCPZ, but I think I might fry the ...
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What is the best way to measure current and voltage through a diode

I am reading the book Learning the art of electronics and on a part about diodes, the author pointed out that in characterizing a diode(I, V relation ) there is an unavoidable error due to the ammeter ...
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Multimeter not reading capacitance accurately?

I am trying to measure new electrolytic capacitors before they go into my guitar amp to make sure that they are up to spec. I'm using a Morris #57044 multimeter, which has an autoranging capacitance ...
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61 views

How to measure current at output port

I have programmable current source in the board. The circuit blocks in the board is, Microcontroller => DAC => Amplifier => Output port I want to measure the current for range of DAC code to verify ...
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31 views

How to test bipolar linear integrated circuit (voltage detector) using a DMM

I have an IC (KIA7025AP) on my power PCB. I need to check if it's faulty. Function of this IC is accurately resetting the system after detecting voltage at the time of switching power on and ...
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51 views

Diode testing: rising voltage in reverse direction?

I have some AUK diodes (http://www.kodenshi-tk.co.jp/products/power_semi_device/pdf/power_diode_02/14-19_SF10A400HDS.pdf) set in a Samsung X-sustain buffer board for a Plasma TV (PCB number LJ41-...
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34 views

Current decreasing while measuring the current through a constant current source resistor

My Circuit : The above is my circuit. The Forward drop of LEDs is typically 2.8V and a maximum of 3.15V. I designed the current through the string to be around 21mA, so the emitter resistor is ...
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Multimeter diode mode: do different multimeters show the same results approximately?

I think that in many cases the voltage that a multimeter shows in diode mode is dependent on the current it uses for that mode. So the values measured by different multimeters in diode mode should be ...
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106 views

How to check with a simple multimeter whether an old lead-acid battery and its charger are still working?

I have an old (ca. 10 years old) 6V lead-acid battery and a mains charger for it and I know the combination worked years ago. Now I tried to recharge the battery and the charger's LED turns on ...
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How to test if a capacitor is good if my DMM farad's range is less than the capacitor's

So I found out that my DMM maximum reading is 100uF (Though its price is twice the ones that reads upto 100mF, mostly because its 8 years old). It doesn't have manual range for capacitance measurement,...
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testing a schottky diode

I'm trying to find how i can test a schottky diode to check it's state but can only find info on 2 pin diodes. The particular diode is this: http://pdf.dzsc.com/2017/20161120/20161120081219688637.pdf ...
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Power supply module on breadboard giving too much voltage

I'm currently following the tutorial "Electronics Fun Kit" by ELEGOO. The goal is to connect the power supply module with the breadboard in order to provide a 3.3V / 5 V source. After connecting the ...
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Experiment - measuring current across two resistors

My goal is to measure current at different points in the circuit. I took breadboard, D battery, two resistors and multimeter. Here is how my circuit looks schematically: Using multimeter I checked: D ...
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Wrong Multimeter connection / floating ground

What does happen if you connect a multimeter without COMmon ground? Like in this question (Why does a permanent, non-moving magnet, stuck to a long piece of metal generate a voltage?) How would a ...
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Is the quantization error and random error included in the of-range error for multimeters?

When I am looking at a datasheet for a DMM (Digital Multimeter) to calculate the accuracy of a measurement it specifies two error sources: of-range and of-value (also called of-reading). For example ...
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Why I can't measure the output voltage in a LED light bulb?

Why I can't measure the output voltage in a LED light bulb using multimeter? See the picture below :
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108 views

Why is there a difference in the voltage drop across the same resistor when using an oscilloscope and a multimeter?

I am measuring the voltage drop across a 1 ohm resistor within a circuit with an oscilloscope and a multimeter. The impedance of the oscilloscope is 1M ohm and the impedance of the multimeter is 10M ...
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49 views

Naming 6000 counts multimeter in digit format

A 4-digit multimeter is also called 9999 counts; and it is called 4-digit because all four digits can display numbers from 0 to 9. A 3½ digit multimeter is called 1999 counts; and it is called 3½ ...
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73 views

Why does the value increase constantly and slowly in diode mode?

I am using Fluke multimeter and trying fix electronic circuit. In diode mode fluke docs, telling briefly explained how to test the durability and accuracy of diodes. The test usually runs when I touch ...
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68 views

Multimeter cannot read below 200ma

I just got a Ultrics FBA-0021-YB multimeter and tried to measure some currents. This multimeter has 2 modes of measuring current, one is by connecting the red lead to the 10ADC (10A max) slot, and ...
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90 views

Two of the same resistors have different resistance?

I am doing some work on the electronics of a guitar and in doing so was testing some old circuitry. I noticed that there are two resistors each stamped with ‘223’. When checking the resistance of ...

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