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.

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Scalable Voltage Display

I am trying to create my first PCB, and I am trying to measure and display scaled voltage and current output from a few different sensors on several seven segment displays. For example, one of the ...
tyster02's user avatar
4 votes
6 answers
1k views

Circuit current flow

I have a question which might be somewhat classed as newbie but I may have massively overlooked this concept and changes my understand greatly if true. Looking at the image, the voltmeter measuring ...
Smuggler's user avatar
1 vote
4 answers
145 views

Understanding input pins [closed]

I am trying to gain a better understanding of input pins. As per my current understanding, they act as a voltmeter with super high resistance and are connected to the ground on one side. When ...
Tomer Gigi's user avatar
1 vote
2 answers
86 views

Reading voltage across Christmas light wires, multimeter shows erratic readings

I am attempting to splice a simple on/off switch into a strand of Christmas lights. Previously, I separated the two wires and cut open the one marked with dots, expecting it to be the positive/live ...
Riccardo Orlando's user avatar
1 vote
1 answer
126 views

Peak voltmeter detector explanation

I'm designing a peak sinusoidal and impulse detector, based on the old design of a peak voltmeter designed by Haefely. I have the schematic, but I can't understand how this circuit works. The large ...
juliancaba's user avatar
1 vote
2 answers
148 views

Dual Slope integrator voltmeter improvement in Design

So, I'm attempting to design a dual-slope integrator voltmeter. I have the following block diagram so far. Now an AVR microcontroller will have an ADC pin in the range of 0-5 Volts . So negative ...
Zipho Lunika's user avatar
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4 answers
127 views

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) ...
NonComposMentis's user avatar
5 votes
4 answers
2k views

Voltage in a Short Circuit

I am very confused about voltage in short circuit. Let's suppose there is a 6 volt battery and both ends of it are connected with the same wire and it's short-circuited. Then because resistance of ...
Rajveer khajuria's user avatar
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1 answer
132 views

Voltage divider circuit for DC voltage measurement with protection against AC voltage?

Need some help with making a simple voltage divider to sense DC voltage of 0-30 V range with my DAQ which accepts 0-10 V analog input. I was wondering if the input voltage is by mistake an AC voltage, ...
Shamooooot's user avatar
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3 answers
187 views

Can I use this voltmeter / ammeter without the shunt supplied along with it?

I bought this voltmeter online. It does not show current. Do I need to use 10 A load for some reading or it will work for lower amps also like 1 to 2 A? From the product details: Measure Current: ...
Naveed AA's user avatar
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2 answers
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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.
Shamooooot's user avatar
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Measuring voltage across a rheostat

I want to measure the voltage across a rheostat. For this purpose I connected a voltmeter in parallel to it, but even on turning on the circuit there was no deflection in the voltmeter whatsoever. ...
NewUser25's user avatar
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1 answer
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DIY voltmeter safety concerns

I would like to build a voltmeter using an ATMEGA328P that measures AC mains voltage. I came across the following schematic which appears to be what I am looking for: The top part of the circuit goes ...
jhorv's user avatar
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1 answer
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Very, very sensitive (but possibly very inaccurate) method of detecting voltage differences

I have a test setup where I need to be able to tell if there is a voltage differential between 2 nodes, but not affect the circuit at all. Some would suggest to using the voltmeter function in a ...
Tempus Nomen's user avatar
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1 answer
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Will an AC voltmeter show deflection if connected across a pure inductor in an AC LCR circuit?

I'm asking this on behalf of one of my classmates. My thoughts: It will, as if there is current flowing backwards, there needs to be an EMF developed, and if there is no voltage drop, Kirchhoff's laws ...
math and physics forever's user avatar
3 votes
2 answers
853 views

How can I increase the full scale of an analog voltmeter and analog current meter or ammeter?

I have been researching about this for a long time and all I am finding is about 1mA full scale reading. I do not know what it means even. Why do we need to flow 1mA all the time? If I want to create ...
Obiick's user avatar
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31 votes
3 answers
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What does this symbol on a voltmeter looking like an upside down U with a small line under it represent?

I decided to start a new question because I have no idea what word describes it at best, let alone to do a research (aka googling) which can be a bit inconclusive. At first glance, it looks like it ...
Yudhi G.'s user avatar
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AC voltmeter circuit

I was searching a way to get the VRMS of an AC voltage. The main transformer drops down the 230 VAC to 15 VAC and with a potentiometer I'd like to display it on a DC digital voltmeter (the AC ...
philfs's user avatar
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3 answers
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Is it normal that an analog voltmeter has about 7K ohm input impedance?

I have bought 10V 6c2 DC analog voltmeter, and I have tested it with a regulated DC power supply and it measured pretty accurately different voltages, however when I tried measuring the voltages in a ...
Shamooooot's user avatar
2 votes
1 answer
130 views

Best way to measure microvolt potentials in an electrolyte solution?

I wish to measure microvolt-level fluctuations in a small volume of electrolyte solution, currently saltwater. My existing setup works but has some strange data so I'm hoping someone with more ...
drc's user avatar
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Determining Polarity Of Unmarked AC Adapter With Voltmeter

I need to replace an adapter that no longer works (for a fibre optic Christmas tree). I do not see any indications for polarity on the adapter (or anywhere else) and I do not have the manual. I read ...
Ken Boone's user avatar
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1 answer
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Confusing results from reading voltage

I have a pasteurizer machine and I'm trying to find out the voltage of the heating element. The circuit in the image shows the connection. Hot wire goes into the thermostat at point A then exits at ...
blah's user avatar
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1 vote
1 answer
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How do I calculate accuracy marked as ±(4 ppm rdg + 10Digit)?

Trying to figure out the correct way to calculate accuracy with LSD. I looked at a few sources, but I'm still confused on the topic. The question: A digital voltmeter can display counts up to 1999999 ...
Acapella's user avatar
-1 votes
1 answer
118 views

Voltage measurement with diode connected to the motor

simulate this circuit – Schematic created using CircuitLab Why doesn't the diode short circuit when I press the button even though I have a diode installed (parts intact)? (I tried in real life.)...
Jundullah's user avatar
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1 answer
155 views

Digital voltmeter and power supply design

I have a digital voltmeter, it has 3 pins, 2 for power and 1 for measurements, if I connect its ground to the circuit's ground, I can measure any 1 point of the circuit, but I can't measure between ...
user avatar
1 vote
2 answers
166 views

Voltmeter internal resistance

Everything is clear and understood, I only don't understand why he added only in the second question and did not add it in the first question Also, what he meant by "If the meter resistance is ...
OMAR's user avatar
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Regarding connecting MOV and SMPS in parallel for electrical meter

We are working on development of a 3 phase electrical metering circuitry. All the 3 phases are connected to metering IC using resistor divider circuitry for voltage measurement (between phase and ...
Malyala Sai Kiran's user avatar
2 votes
2 answers
609 views

Understanding input bias current in operational amplifier

In order to prevent overvoltages on my arduino voltmeter (more than 20v) I decide to add a protection circuit. As i show in the image i use a AD8605 precision op-amp for the purpose. (https://www....
marcosbc's user avatar
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2 answers
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Why is my voltmeter output incorrect

So I'm completely new to electrical design. I thought I'd try out the most basic experiment I could think of. Here I hooked up two AA batteries to a breadboard along with a 10 K resistor. When I ...
Onye's user avatar
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1 vote
1 answer
160 views

Finite input impedance of voltmeters

I have a question regarding the impedance of voltmeters. I learned that a voltmeter can be modeled as follows, where \$R1\$ is the input impedance: simulate this circuit – Schematic created ...
planespotter5000's user avatar
25 votes
7 answers
5k views

How do we know that voltmeters are accurate?

Something that has always puzzled me is how we know the accuracy of voltmeters. From googling around, it seems that today's digital voltmeters use an ADC. An ADC works by comparing the voltage that is ...
John Allen's user avatar
4 votes
2 answers
224 views

Wiring a panel kilovoltmeter

I am planning a design for a high voltage (2.5kV) DC power supply to drive a HeNe laser. I would like to add a panel voltmeter at the power supply output to ensure it's operating correctly. I found a ...
flashbang's user avatar
0 votes
3 answers
1k views

Proteus Simulation of Digital Voltmeter

I have been trying to simulate a counter ram, successive-approximate type voltmeter in Proteus. Below I have tried the simulation of it in Proteus. Everything seems right but I don't get the reading ...
Abi Nand's user avatar
4 votes
1 answer
248 views

Voltmeter resolution increase by having several in series

The problem I am trying to measure quite precisely a voltage around 7.2V on a line of a PCB with a voltmeter. In this voltage range, my voltmeter only displays 3 digits. So the reading is something ...
Tulmandil's user avatar
3 votes
1 answer
225 views

Op-amp selection for reverse polarity protection on an Arduino voltmeter

I made an accurate voltmeter using an Arduino Nano as the microcontroller. What I want now is to add a reverse polarity protection using an op-amp with a gain of 1 without changing the actual accuracy ...
marcosbc's user avatar
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0 votes
1 answer
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Can I power and use 1 small voltmeter for 3 12v batteries in series?

I asked this question for 4 voltmeters before, and received some great feedback. Unfortunately, it generated too much heat. This is the design I'm thinking of implementing now, but I want to make sure ...
KidCraftsman's user avatar
6 votes
4 answers
653 views

Can I power and use 4 small voltmeters for 3 12v batteries in series?

I bought some small voltmeters hoping I could use them with my kid's Razor dirt bike. The bike uses 3 12v lead-acid batteries in series to provide 36 volts to the motor. Ideally, I'd like to use the ...
KidCraftsman's user avatar
1 vote
2 answers
4k views

The issues of common ground with voltmeter and ammeters

Apologies if this post is, yet again, another noob in electronics. I have an engineering degree in audio but have newly found a passion for electronics and am teaching myself as I go. I am trying to ...
Audiosine's user avatar
1 vote
5 answers
781 views

Can a voltmeter itself disturb the exact measuring of voltage?

I'm trying to understand the effect on a system when the voltage of the system is measured by connecting a voltmeter. For example let's say we are trying to measure the voltage of a battery. To ...
Donghoon LEE's user avatar
0 votes
1 answer
302 views

Question regarding chinese voltmeter ammeter module

I am new to this forum. I am a Diploma in Electronics from India and a passionate DIY hobbyist too. I have a question regarding cheap 10 amp ammeter and a voltmeter module I bought off aliexpress. I ...
Alex's user avatar
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0 votes
0 answers
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Resistance measured low in constant DC voltage supply

I have a DC power supply, which I have connected to an electrical circuit on a breadboard whose total or equivalent resistance is to be measured. The power supply comes with a voltage and current ...
hbaromega's user avatar
  • 101
0 votes
3 answers
853 views

Reading voltage of an amplified thermopile

I'm trying to make a circuit for a physics experiment where I measure the voltage output from a thermopile. Because the raw output voltage is in millivolts, I need to use an op-amp circuit to amplify ...
Caspar Broekhuizen's user avatar
1 vote
2 answers
216 views

Which lead of a voltmeter is subtracted from which to get the potential difference?

I'm working on a problem (on paper, not in a lab) in which I'm using the Hall Effect to determine the sign of the charge carriers in a current. In order to get this right, I need to know which end of ...
skrilmps's user avatar
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1 answer
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Question regarding a charger modification for a Dell 3100 docking station

I'm quite new and inexperienced to this so I would appreciate any guidance I can get. Given the quarantine situation I need to work from home more so I purchased a used D3100 docking station but with ...
TImmuh's user avatar
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0 votes
1 answer
103 views

Using a cap to predict the presence of a pulse via voltmeter

I have a pulsed power supply that provides 250v pulses with a pulse width of 2 uS and a frequency of 10 Hz. However, I'm unaware of the polarity of these pulses. In order to detect the polarity of ...
James Li's user avatar
3 votes
0 answers
218 views

Replacing an ammeter with voltmeter?

I have found this circuit of a millivoltmeter, and it seems like something which as a hobbyist I can do it, and the range of the measurement is very suiting one of my projects, but I would like to ...
Nik Lozan's user avatar
1 vote
2 answers
84 views

Explanation for Method of Monitoring Current from a Power Supply

I recently came across an interesting way to monitor current, but was not certain exactly how it works. Likewise, I was hoping that someone might be able to explain how the device measures current. ...
James Li's user avatar
1 vote
0 answers
300 views

Measure 220V alternating current with a multimeter in DC mode

What happens if we measure 220V AC from wall socket with a multimeter in DC mode (instead of AC)? If I remember correctly, it should show the average value of this sinusoidal 220V, i.e. 0V. Is ...
Basj's user avatar
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2 votes
0 answers
205 views

Measuring AC output of variac with DC voltmeter

I have variac (Uin=230V, Uout=0-250V, Imax=5A), where I would like to measure voltage on output on a digital voltmeter. Since I have problems finding digital AC voltmeter 0-300VAC (most of them ...
Jakey's user avatar
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2 votes
1 answer
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Why is my Voltmeter/Ammeter not reading amps correctly?

I am having problems correctly setting up my volt/ammeters. I am attempting to use them to monitor a boost converter I recently purchased. I would like to have one set up on the input of the boost ...
ICEMAN's user avatar
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