# Questions tagged [voltmeter]

A voltmeter, also known as a voltage meter, is an instrument used for measuring the potential difference, or voltage, between two points in an electrical or electronic circuit. Some voltmeters are intended for use in direct current (DC) circuits; others are designed for alternating current (AC) circuits. Specialized voltmeters can measure radio frequency (RF) voltage.

55 questions
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### Precision notation for voltmeters

From the technical details of a multimeter: AC Voltage: - Range and Accuracy: 200mV ± (1.0%+2); 2V ± (0.7%+3); 20 ± (1.0%+3); 200/600V ± (1.2%+3) What does the notation "± (0.7%+3)" mean? ...
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### Proteus voltmeter value in simulation not right

I'm really new to Proteus, so if I'm doing something very wrong, sorry. I'm messing around with the Proteus simulation but I don't understand why my voltmeter has given me a value when the circuit ...
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I'd like to preface with saying that I'm quite new to this. Given emf E = 9 V, and that both resistances are equal, R = 1 kΩ, ...
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### Trying to find the ratio of voltmeters V1/V2

I'm trying to find the ratio of voltmeters V1/V2. My attempt is shown below Let's recall each resistors R and then we'll have V1 = (2R)(I) (since two resistors are in parallel). V2 = (3R/2)I (two ...
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### How to isolate several voltage sources that feed a single voltage meter

I need a way to isolate several voltage sources around a large vehicle that feed a single voltage meter some distance away on a panel. Each source is selected by a momentary-spst (at the source). ...
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### Voltage Question [closed]

How is voltage measured in a voltmeter, is it the difference between the voltages that are measured. If you can, please explain how to do part B of the question.(I am trying to solve this question and ...
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### Issue with 7107 IC

I am having trouble with the 7107 IC. I have 5 of them on my PCB: 3 being used as current measurement and the other 2 are being used as a voltage measurement. Only one of the 5 are displaying ...
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### Solve the ideal diode circuit

assume forward biased replace the diode with iD going down and short circuit it and make VD=0 combine 70Ω and 30Ω resistors that are parallel and it becomes 21Ω now 21Ω ...
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### 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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### Explanation for dual slope DVM voltage measurement

I want to design a dual slope integral digital voltmeter.After reading its working I got a doubt on its voltage measurement. How can we say that our required voltage is the count of t2 time period as ...
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### Commonmode voltage and measurement with voltmeter and an instrumentation amplifier

I'm trying to compare a voltmeter and instrumentation amplifier which both measures voltage. Below in Figure 1, Figure 2 and Figure 3 I made these diagrams to ask my question. Basically a device(on ...
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### Dimmer switches and analogue voltmeters

I want to make a steampunk type table lamp. I want to use a dimmer switch and an old fashioned analogue AC voltmeter to display the "voltage" as a feature/gimmick. This displayed voltage doesn't need ...
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### How can I build my own over voltage protection circuit up to 480 VAC

I am rigging up a portable test panel, will be using a true-meter APM that will do up to 600 VAC or 600 VDC. I would like to be able to use it to measure typical U.S. 120 VAC or 240 VAC and 480 VAC. ...
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### Under what conditions would using a voltmeter be more accurate than an ammeter to measure current?

Suppose you have a simple circuit with a voltage source V1 connected to a resistor R1, like this: simulate this circuit – Schematic created using CircuitLab You could connect an ammeter in ...
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### Digital voltmeter ammeter wrong reading

Hello! I've built a small adjustable PSU with a buck converter (XL4015 module) and a cheap 10A digital voltmeter and ammeter. It worked fine for a few minutes but after that the voltmeter started ...
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### Achieving high-input impedance for a voltmeter front-end

So, I'm starting on the front-end for my digital project, figured out the ratios (100kΩ, 900kΩ, 9MΩ for ÷10 and ÷100), tolerances (0.05% - 0.1%) and temperature coefficients (< 50ppm/°C might work) ...
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### Why is the resistance of an ideal voltmeter infinite?

Consider an analog voltmeter. I understand that the internal resistance of the voltmeter should be high enough to not lower the actual voltage across the load connected to the voltmeter, but, at the ...
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### How to test high voltage Zener Diodes with multimeter?

Given an unknown Zener Diode taken from a circuit board, is it possible to measure the Zener Voltage without a datasheet? I tried to make a circuit like the one below and I add batteries in series ...
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### Simplest and quickest rig to hack an LED Voltmeter for USB interface

I have a few LED Voltmeters that's almost identical to this: I need to log fairly DC voltages for long spans. Sampling every few second or fractions of seconds or so. I know decoding the exact digits ...
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### Measuring voltage with different voltmeters in parallel - influences?

Let's say we're measuring voltage of a battery with three different voltmeters in parallel, as is shown in the picture: Would those voltmeters influence each other because of their finite internal ...
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### Can I apply a 24v DC current to an analog voltmeter graduated between 8 and 16v for a few seconds?

I have an analog voltmeter that is used to monitor 12V batteries, with a needle going between 8V and 16V) In a specific situation, I have a series/parallel switch which turns two of my batteries into ...
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### How do I measure internal resistence of voltmeter without ammeter?

I know how to do it with ammeter, but how can I find internal resistence without ammeter?
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### How to measure line voltage (220V) with an arduino?

I'm a Electrical Engineering student and I want to sense and sample the voltage signal coming from a wall socket (110V - 220V). I came up with the following circuit using a voltage divider with high ...
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### Why would my signal from a piezoelectric device changes while using a voltmeter and electrometer?

When we apply a force to a piezoelectric material it produces some potential difference. I was measuring with Keithley nanovoltmeter and Keithley electrometer 6514. I am getting different output in ...
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### proteus dc voltmeter and ammeter results are not accurate / non existent!

I'm a beginner to Proteus and was just exploring simple circuits and trying out different things on the simulator. I built this simple circuit with a potentiometer and an led and measured current and ...
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### The voltage drops measured across very high value resistors do not add up - why is that? [duplicate]

I have a very simple series circuit which I originally built hoping to measure voltage from an Arduino, but while calibrating realized an irregularity, so stripped it down to its basic parts. ...
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### Working Principle of Digital Voltmeter

This cite originates from https://www.electrical4u.com/digital-voltmeters-working-principle-of-digital-voltmeter/ is on how digital voltmeter works: Unknown voltage signal is fed to the pulse ...
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### What is this VU-meter?

I just made a "home made" adjustable power supply and I want to attach a voltmeter to the output so I can easily set voltage using a potentiometer. I don't want to complicate my circuit with a ...
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### high resolution analog AC voltmeter mystery

I have an old Pekly multimeter that can be seen here. This is an analog multimeter, and only its Ohm-meter needs batteries. It can measure current intensities, DC and AC voltages, and resistances. The ...
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### analog to digital converter as voltmeter [closed]

I'm still student so excuse me if the question is not professional. Basically ADC can convert any voltage within decided range to the digital form. Isn't that what exactly the digital voltmeter ...
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### Voltage measurement using the following circuit

I was given the following circuit for a mains-voltage measurement system. The oscilloscope in the schematic is meant to analyze a low voltage representation of the mains voltage supply. After ...
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### Design a Voltmeter using BJT [closed]

How to design a voltmeter using BJT and minimal other components to measure between 0-5V in 10 different steps(i.e 0-0.5,0.5-1,so on).Explain its working to.
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### “Equivalent resistance” of diode as $V/I$ used to evaluate an approximation

Consider the circuit in picture, used to measure the voltage across diode and current flowing through it. simulate this circuit – Schematic created using CircuitLab With this circuit I do ...
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### make a 2 wire voltmeter w/led bulb display

So I've been working on a project for a while now and I'm looking to create a specific feedback for the user. What I want to do is to make a 2-wire voltmeter that operates similar to this one. (Click ...
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### What Determines the Noise Bandwidth of a DC Voltmeter?

Say I have a 1000 Ohm resistor. At room temperature, this has 4 nV/rtHz of Johnson Noise. That means that a measurement with a bandwidth of 100 Hz would see 40 nV of RMS noise. If I were to connect ...
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### Relation between internal resistance and chosen scale on analog/digital voltmeter/ammeter

On Introductory Circuit Analysis of Boylestad I found out the following about the relation of internal resistance of a multimeter with the scale choosen on the instrument. Analog voltmeter: internal ...
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### Voltmeter vu-meter dynamo

To start, I have no experience with electronics except what I've been googling the past week. What I'm having issues with is finding a way to make a voltmeter that functions like an led vu-meter would....
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### Why the voltage in a circuit changes when the battery has a resistance but not when the battery doesn't has a resistance?

I was learning the basics of electronics with an interactive simulation of a DC circuit on phet.colorado.edu and I notice this weird pattern. And also, in real life, with a real battery, what rule ...
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### Experiment instrumentation & Measurements

In doing the experiment on signal conditioning(rc band pass filter) why was the oscilloscope is a better choice than the voltmeter for voltage measurement?
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### DC voltmeter yields a value with 21% error

In the following circuit, the dc voltmeter yields -2.36V while the analytical value is -3V which means there is an error of 21%. The error is rather huge. I've searched through the documentation but ...
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### Odd reading when replacing an LED with a voltmeter on a PNP's collector

I am using a simple circuit to drive a 12V LED with Arduino. I have used this circuit successfully in past. I am using NPN-PNP combination to drive a load which needs more Voltage than Arduino's HIGH ...
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### Which Ampere range and precision does my amperometer need to monitor a current of 220V between 50W and 300W

I need to measure the evolution of the electric power at the level of the electric plug of a computer in function of its CPU usage percentage. The voltage is 220V and the wattage between 50W and 300W....
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### What is an analog meter (volt/ammeter) with the needle in the middle called?

I am making a demonstration which requires me to have access to a small extension that helps me prove Faraday's Law of Induction actually induces a current in a ...
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### Convert Ammeter to Voltmeter

I've got an old analog (0-5ma) ammeter and want to convert it to measure 0-±5 volts, as an output for my Arduino. I'm a programmer and my knowledge of electronics is limited. I know what components ...
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### Confused by voltmeter reading in DC parallel circuit problem

I am a beginner and have been doing some circuit problems from a book. However I am confused about this one: simulate this circuit – Schematic created using CircuitLab Question: Assume a 9V ...
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### Using a voltmeter to measure RMS value of a sine signal with a DC offset

Imagine you have a periodic signal F which is nothing but a sinewave (S) plus some DC offset (D). Here is an illustration of such signal: Imagine I want to measure the RMS value of this signal F. ...
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### Connecting a Volt Ammeter to the input and output of a power supply

I'm working on a mini adjustable power supply that can give me a steady max of 12 volts, 3A and be able to boost to 24V when needed. Therefore, to do so I'm using a MT3608 2A DC-DC Step Up Power ...
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### Measuring 0-250V and 10A (AC) with arduino

So, I've decided to make a "homemade variac", but for simple things, such as lightbulbs, etc. Just to try things. So I'm going to use a voltage regulator to regulate AC voltage between 0 and 230V, ...