Questions tagged [multimeter]
A multifunction measuring instrument used for measuring AC and DC voltage [V] and current [A] as well as resistance [Ω]. Many digital multimeters can also measure frequency [Hz], duty cycle [%], capacitance [F], temperature [°C], and/or other electrical or physical properties. Most are handheld; more expensive bench models are also available for applications requiring high precision.
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Connecting a multi meter across a single resistor
simulate this circuit – Schematic created using CircuitLab
When I connect a multi meter to AB it shows 5V, but isn't the resistor supposed to decrease the voltage/current? V=IR (5 = I*1000) ...
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How can I check continuity longer than my probes?
I'm trying to sleuth out a wrongly wired connection on a small injection molding machine. I'm starting by verifying the connections match the diagrams from the manufacturer. However, some of the ...
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Multimeter Negative Resistance
I have a Fluke 87V multimeter and sometimes when I measure some resistors (in power supply PCBs I saw it) it shows me negative value of resistance. Why this? It is some flaw of the multimeter or it ...
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What result does digital multimeter show when measuring filtered AC V? Is it Vavg or Vrms of the ripple voltage? What's the formula to calculate? [closed]
Can somebody tell me what result does multimeter show when measuring filtered AC V? Is it V avg or V rms of the voltage ripple? And what's the formulas to calculate this?
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Why does an AC Voltage reading on a DMM decrease as the frequency is increased?
I'm doing an assignment for a lab and I've found that frequency doesn't affect the voltage reading of an oscilloscope while it does for a DMM. Online, it says this is because an oscilloscope displays ...
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How can I measure the resistance of non-linear devices using a digital multimeter?
Is the value of resistance that appears when we measure the resistance using a DMM at the terminals of any electronic device the total equivalent resistance of that device which is also called load ...
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Measuring electric generator AC frequency
I need to measure the AC frequency of a 230 V electric generator (gasoline powered).
I have a cheap but ok multimeter that does Hz but the reading is erratic (some 1 kHz...)
The reading on the mains ...
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Why does loading a circuit cause voltage drop in DVOM?
So this question relates to cars but applies to all electronic circuits really.
I was watching a car diagnostic video on youtube and in the video he demonstrates the difference between doing voltage ...
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Did a blown fuse in my multimeter damage my multimeter?
May be a little newbie question, but I since I am an electronics beginner and couldn’t find a direct answer I will ask it.
I blew the 600 mA fuse on my brand new multimeter, I think I didn’t change ...
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Multimeter range
I've been using a small multimeter meter and the problem is that anytime I want to measure amperage that exceeds 200 mA, I have to switch the red probe the 10 A port. Unfortunately, I can't get the ...
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Measuring voltage but no power with DMM
Hello guys i am a novice electronic engineer and i run up to a question on some troubleshooting i was doing.
I have an old audio door phone system that has 2 designed outputs for the 12VAC electric ...
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Resistors value changes when measured
I've searched this forum for the past few days and I didn't find any solutions or problems similar to mine.
I'm working with a ne555 in astable mode with a configuration that, theoretically, should ...
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Estimation of measurements with a multimeter
I have an EMU-APS PCI sound card which was damaged by a bad PC power supply.
The card is old but costly to replace and of very high capability, so I am attempting to repair it.
As it is a proprietary ...
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Resistance measurement: Agilent 34401A vs. Fluke 179
I was attempting to measure isolation resistance between the output of an isolated DC/DC converter to machine chassis. I was somewhat surprised to see a large difference in measurement between a 6 1/2 ...
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Measuring Inverting Op Amp config and not getting desired output (practice)
I am a year 2 EE student and I'm still struggling with getting simulations to work in practice.
Components:
10k resistor x2
Arduino
LM741 Op Amp (pinout: https://www.ti.com/lit/ds/symlink/lm741.pdf)
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Why can't capacitors on PCBs be measured with a multimeter?
While looking at this article, it mentioned that one cannot test the capacitance of a capacitor while it is on a PCB. The explanation given is:
The reason is, that when a capacitor is inside the ...
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Resolution versus sensitivity of a multimeter
I am trying to understand the difference between resolution and sensitivity. After searching on the internet and the youtube I found more or less the below definition, but in practice I can't ...
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How should I test my USB cables?
Some time ago, I purchased the FNB58 USB multimeter from FNIRSI with the intention of testing some of my USB cables. Ideally, I wanted to throw away those that are redundant and/or those that pose a ...
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Why aren't I getting a voltage reading from my AC/DC power adapter
I am new to electrical engineering.
I cut the barrel jack off the end of a 24V DC power adapter, exposing a red and white wire. I'm trying to determine the polarity of the red and white wires with a ...
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Spooky multimeter AC reading using 1 lead
I'm fixing an ultrasonic cleaner board that isn't working. There's a small transformer that drives the transducer. When I set my DMM to AC and touch both leads on its output, there's no reading. If, ...
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Zero voltage on voltmeter means zero resistance and infinite resistance?
I am pretty sure this is a very easy question but I am having brain lag, on a digital/analog voltmeter, what is the difference between zero volts (or very close to zero i.e. 10 mV, -4 mV ) when the ...
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What would be the voltage reading at point B when the circuit is supplied with two different voltages?
The given circuit has one fixed resistor connected in series with a bulb. When 12V is supplied, there is a reading of 8V at point B.
However, when the same circuit is supplied with another source of ...
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What would my DC meter on my digital multimeter measure if I was scoping a digital signal?
If I measure an AC voltage it shows 0 Volts. If for example I have a rectangular pulse from 0 to 5 V with 25% duty cycle the meter will show 1.25 volts?
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Multimeter blown trying to measure 125 V in the 600 V AC range
I used a multimeter in its 600 V AC range to measure the voltage across a socket of a surge protector that is rated 125 V - 5A.
As soon as I inserted the test leads, there was a pop and a bright flash....
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What is the benefit of using a 10MΩ resistor in parallel with a current shunt?
I am reading the Operators Manual for the Fluke 8588A Reference DMM and came across this:
The DCI Ext Shunt function provides a calculated current reading for a specified current shunt by measuring ...
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Ammeter showing wrong value
I am trying to figure out why the multimeter is not displaying the right current.
I purchased a bayite DC 6.5-100V 0-100A LCD display digital current voltage power energy meter multimeter ammeter ...
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DMM showing voltage when one lead is hanging in air
My meter gives me a reading when I connect the positive lead to something and the com lead is just hanging there. Is this the voltage difference between the air and what ever my positive lead is ...
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How can some multimeters automatically detect and measure the AC and DC voltage and current?
I was wondering how there are multimeters that are able to measure voltage and current AC or DC automatically without setting the reading on AC or DC.
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Add buzzer to multimeter
How can I add a buzzer to my EverStart Digital Multimeter 10711WDI circuit board, so that it buzzes when there is continuity?
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HP/Agilent 34401A low beep sound level
I want to modify the internal beep sound pressure level of this bench DMM and make it louder.
I have a problem with my ears and I won't be able to hear the the beep sound well when making continuity ...
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"buzzing" sensation from a touch dimmer when touched with wet hand
My house has the above touch dimmers from the late 70's or 80's. They usually give off an imperceptible buzz or no sensation when used.
Today I unthinkingly touched one with a wet hand and felt a ...
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Why isn't it easy to put an ampere-meter into any battery driven electronics?
I can buy a cheap multimeter which has an ampere-meter function. Great.
Battery driven computer equipment like laptops and cellphones are complex, and for power / battery management I suppose an ...
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Cheap China solar water pump kit only runs for 10 minutes [closed]
I checked everything with a multimeter, everything seems fine. The batteries charge to full capacity. The output from the solar panel seems correct. The output from the controller seems correct.
In ...
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Trying to get a replacement set of probes for an old multimeter
Summary:
I am looking for the correct terminology to describe probes from an obsolete multimeter so that I can use this information to find replacements myself.
I am not asking for specific ...
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Simple multimeter test
I have a very simple issue. Maybe it is because I am very new to electronics.
Say I have 9 V DC source and a 1 kΩ resistor. Negative is connected to one end of resistor and positive to another end. ...
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Measuring voltage across one end of a 50 ohm bias T and the other end is 50 ohm terminated
I was looking to measure the output voltage from one of the PCBs using a multimeter. I connected the center of the 50 ohm T adapter to the DMM, one end of the T adapter to the output port of the DUT i....
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Why is my multimeter not measuring current?
I'm doing a little bit of experimentation with a glass of water and a 9 V battery. I added a little bit of salt to the water, and I measure the resistance in the water from probe to probe to be ~60 kΩ....
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Utility of a load resistance for measuring another resistance
In this paper they need to measure the value of an unknown resistance RS, whose value is the output signal of a sensor. However, instead of measuring this resistance directly with a multimeter, they ...
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How do you safely measure large AC currents using a multimeter without a current clamp?
I would like to measure the RMS current draw of several house appliances, in addition to the primary and secondary side current of a step-down transformer.
Simply placing my multimeter in series with ...
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Fluke 393 checked resistance on a live circuit wonder if I damaged my meter
I have a fluke-393 multimeter and I was testing voltage on a 480V circuit didn’t realize I was on resistance and when I put my probes on the circuit there was a small arc, quickly taking my probes off ...
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What USB device can I use to check for voltage on or off? [closed]
I am looking for a device (ideally a USB device) which I can use to check automatically if there is some voltage (3.3 V) at an electrical connection.
The idea is to automatically test (with a python ...
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Which electrical components can be measured while still soldered to a PCB already, and under which circumstances? [closed]
I can't seem to find a coherent and thorough answer to this question anywhere on the internet. I know about this Stack Exchange post asking a similar question in the title but none of the answers ...
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Multimeter fails to measure current but voltage, resistance and continuity measurements work fine. Is the fuse blown?
I am trying to measure the current of a pretty simple circuit consisting of an LED, resistor and 9V battery. As I said measuring the voltage, resistance, continuity works fine but the current ...
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Watt meter and load
I have recently purchased a watt meter from Adafruit to measure the cumulative watthours of a non-constant (DC) current.
When I use a multimeter to test the voltage and amperage, I get what I expect: ...
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How can an analog multimeter have a combined mV and µA scale?
Looking at analog multimeters on Amazon I came across several that have one switch position that appears combined for the lowest V and µA settings. I've used various analog multimeters over many years ...
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NEMA 17 motor not turning
I just bought a NEMA 17 motor and some DRV2285 drivers and am following this tutorial.
Originally, the problem was that the stepper motors weren't turning, only vibrating. I was able to adjust the ...
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CAT ratings and DC voltages
I'm a bit lost about the CAT ratings (protection ratings) for oscilloscopes (and multi-meters).
There are many tables for which category is needed for which application (for example here or here,) but ...
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What lead of a voltmeter is subtracted from the other to get the voltage?
As far as I understand, voltage is a difference of potential energy between two points, and that current flows from the negative to the positive pole of a battery in a circuit.
Thus, according to ...
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Analog multimeter reading DC voltage unprecisely
How do we fix and/or calibrate an analog multimeter reading DC voltage rather inaccurately?
24 V is read 26 V
12 V is read 13 V
1.25 V is read 1.5 V
It worked normally three years ago. It was left ...
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Why does my multimeter measure different resistance values?
I am trying to find a fault on a multilayer board currently. I use mostly my multimeter in buzzer mode and came across such a situation.
When I measured a 1 kΩ resistor in buzzer mode it didn't beep ...
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