Questions tagged [voltage-measurement]

Act of measuring voltage

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Arduino Every Nano with 3.7V Li-Po - Reading voltage

I have Arduino Every Nano and 3.7V Li-Po battery (Akyga LP903759). I want to read the current voltage of a battery using analog pin. If I use a 50 kOhm and 200 kOhm resistor (in voltage divider) I'll ...
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Where does the 1V voltage come from?

I have a four PLC with many digital I/O connected similarly to the schematic below. If I use multi meter and measure the voltage between the two points in the schematic, why is it showing 1V? Isn't it ...
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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 ...
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How to calculate the maximum voltage of square signal from Erms?

How do you calculate the maximum oltage from Erms when you have dc and ac component?
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Error Analysis due to Voltmeter Constraints

I got a situation: at the moment I am unable to access both channels for Keithley 2182A nanovoltmeter using LabVIEW. However, for some odd reason, while I cannot access the channels at once, LabVIEW ...
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350 views

Auto Scaling in a Multimeter

I’m trying to create a multimeter, I’ll be mainly using a 16 bit ADC (ADS1115), an ESP8266 on Node MCU, I’ll use the MCU to communicate with a phone app to switch between different multimeter modes, i....
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Is a 90V output spike normal for a 45V buck boost converter?

The LT5176 buck boost converter outputs a short 90-91 volt spike at at the output in the 2nd second after startup, applying power to Vin. Schematic More details at Why does this buck boost with dual ...
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2 votes
2 answers
326 views

Measuring the minimum voltage square wave

I would like to measure if an 1 kHz square wave signal ±12V 10-80% duty-cycle has a minimum voltage of -11V at Vm. simulate this circuit – Schematic created using CircuitLab So I would like to ...
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How do Fuel gauge ICs compensate for battery aging?

I came across this Fuel gauge IC recently and although I understand how the SOC is determined, I do not understand how the age compensation constant(the one used to determine the actual SOC) is ...
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What's the per phase equivalent circuit of induction motor with asymmetric windings?

We know that there's T equivalent circuit and inverse Γ-equivalent circuit for 3 phase induction motor(IM). When the IM is operating under normal situation, the windings are symmetrical, so all 3 ...
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92 views

Check if two voltages (with different grounds) are within 0.5 V of each other

I have designed the following circuit that should be able to detect if two voltages Bus Bar VBAT and VBAT that are referenced to Bus Bar GND and GND, respectively, are within 0.5 V of each other. On ...
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How to accurately measure average temperature of a heating element?

Problem I'm trying to very accurately measure the heat of a nichrome wire as current is passed through it. My approach thus far has been to monitor current and voltage across the heating element and ...
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Help in understanding a Capacitive Voltage Transformer

I have been reading up about CVT’s and trying to comprehend some of the parts of the typical circuit which include: A potential divider (C1 & C2). An inductor tapped from the potential divider. A ...
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How to measure the voltage of a battery under load to roughly estimate remaining charge?

I am designing a system where I'll need to use a micro controller to measure the voltage of a 12V lead acid battery to determine it's state of charge. I was planning to simply use a voltage divider ...
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Design-check; Finding practical accuracy of a DIY voltage-current-temperature meter

What I plan to do I'm building a DIY current-voltage-temperature meter. I felt the need for a mV meter, with a good accuracy down to 0.1mV, a mA meter with accuracy down to 1uA and an optional K-type ...
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1 answer
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How do I scale a differential signal

I am trying to automatically measure the behavior of a batch of devices in order to guarantee that the current stays in the expected range for different supply voltages. For that purpose I am using an ...
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How to convert raw ADC value into voltage in volts in software?

Let's say I have a microcontroller with an ADC and my goal is to measure instantaneous values of the line to line voltage of the three phase grid 400 V/50 Hz. I have a voltage instrument transformer ...
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Why is my PAC1934 voltage/current sensor showing lower voltage?

I'm testing out a PAC1934 click voltage/current meter and am getting weird results. The PAC1934 board is connected to an ESP32 development board, from which it gets 3V3 power and I2C control. There ...
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Bus Bar voltage calculations for renewable integration to grid

I am confused on the problem bellow I started off by use P=IV = V^2/Z --> V=sqrt(P*Z) Assume at each bus bar the power from the PV is being given to the grid with +6KW from knowning that the PV ...
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Voltage Drop/Sag - Current Limited Source

I'm tinkering with the idea of adding a display for gear position on my motorcycle. It already has a gear position sensor that connects a different resistor in series to ground, depending on the gear ...
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Light sensor circuit

Hello for homework assignment I have to design an electric circuit which takes input from a light sensor and finds if the brightness is bigger than some value. This is what I have done so far: ...
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AC Power measurement ( digital sampling)

i want to measure AC power and i want to know what is the best and safest way to digital sample AC voltage and AC current? For AC voltage: We can use voltage divider and feed it to ADC with reference ...
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Measuring average DC of pulsed analog signal

I'm trying to measure average DC level of pulsed analog signal. The pulses have minimum pulse width of 10 us and amplitude of max 5 V. Pulses are somewhat gaussian shape and have very random height ...
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Four wire voltage sensing, all four wires in one cable?

If I twist the power positive and negative wire together and do the same for the sensing wires, can all four wires (two twisted pair) be in one cable or they should be physically separated from each ...
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101 views

High voltage coaxial probe measurements

I am designing a high voltage motor controller and I want to validate the switching circuitry to ensure there's no excessive ringing behavior. I had an idea to use something like an SMA or u.FL ...
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Measuring just half the sine wave of a current measuring transformer?

I'd like to measure current of electrical devices using one of those split-core transformers you clip around an AC wire, which has a built in shunt resistor and hence outputs a voltage. I'd like to to ...
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1 vote
1 answer
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ACS71020 Connecting and reading voltage properly

I am using an ACS71020 3.3 V I2C version hooked up to an ESP32. I have connected the IC as proposed in the datasheet. Rsense used is 1.8 kΩ as proposed in the evaluation board user manual for 230-240 ...
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148 views

High quasi-isolated voltage measurement

I have to measure a DC voltage and an AC voltage around 100V. I found the circuit with an AD629 and one OP177. I simulated everything in Spice and it works fine, at least in the simulation. In ...
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Using a switching DC-DC converter in high dynamic range current/voltage sensing

I'm thinking of making a power meter circuit which will have a high-side current-sensing amp (LTC6102), a resistive voltage divider for sensing the voltage, a dual op-amp (OPA2365) as a buffer for the ...
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Precision battery voltage meter, Auto adjustment by R-2R

For a more precise measurement of a battery voltage I'd like to apply auto adjustment. The input voltage ranges from 2.5V-4.2V (single cell) to 20V-72V (module). At the moment the input voltage is ...
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  • 11
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361 views

4-wire voltage sensing for DC load

I'm building an electronic DC load. I'd like to implement voltage sensing (4-wire sensing). I made this schematic: Input voltage can be up to 60V, this circuit basically divides it by 6, and output ...
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Multimeter shows 4.3V AC AND DC

Today I wanted o repair my door's buzzer system. After removing the front, there were a number of cables protruding from the wall. Pretty old building, so there was no clear color coding of the cables....
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Characteristic of LEDs

I measured with an oscilloscope the characteristic of three LEDs (green, red and yellow) connected in series with a 1000 Ohm resistor. The result of the measurement was this figure: Why do I have ...
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Multimeter fails to measure forward voltage

I have a MS8233D Multimeter and wanted to measure the forward voltage of some LEDs. I connected the leads directly to the LED and used the Diode Testing Mode. However the multimeter just displays Ol ...
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742 views

Measuring voltage between two points

I Have the following Schematic: The book i am using ask for \$V_{BC}\$ which I found by \$V(B) - V(C) = 0V - 9V = -9V\$ The book gives the answer as 9V, is it safe to assume that since voltage is ...
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1 vote
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Settings for multiple variable resistors in a logic probe

I am building what looks on paper like a really sweet logic probe as a first project. It includes 3 variable resistors. The site I got the circuit diagram from is translated into english and doesn't ...
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84 views

Measuring battery voltage fluctuations and spikes in an analog wall mounted clock when the second hand ticks

As the title suggests, my goal is to be able to pickup minute voltage fluctuations of an AA battery cell of the wall-mounted clock, each time the second hand ticks. My first intuition would be to ac-...
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362 views

Need help with generating a bi-phasic current

I'm trying to generate a symmetric biphasic current pulse using a Grass S88 Stimulator. Here's a diagram: SG is a signal generator with two outputs, S1 and S2, which are generating a periodic pulse ...
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1 answer
555 views

Measuring input voltage with 3.3V ADC MCU

I am designing my very first DC motor driver circuit. Right at the start, I want to be able to measure the input voltage to the system. The system supposed to work with external DC power supply from ...
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  • 573
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1 answer
93 views

Old 9v battery - Strange Behavior

The battery in my garage door remote finally quit. Before replacing it, I measured the voltage with a digital multimeter and was surprised to find it reading 9.70v, quite a bit higher than the ...
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Current measurements for a DC motor being rectified when in reverse direction (differential low pass filter implementation)

Recently for a project I've been trying to capture voltage and current characteristics for a DC motor. To measure current, I'm using a single resistor (R1) in series with the motor, and feeding the ...
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2 answers
63 views

Using transformer secondaries for audio amp

I have a old transformer out of an audio amp and want to repurpose it for another DIY amp project using the LM3876. There is a 5 pin connector for the secondaries. I checked voltage potentials across ...
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Noise in measurement

I'm having a problem when I measure a voltage from a lead battery. I provide my circuit so you can understand better whats happening. For example I measure a 24 V battery, goes to a resistor divider ...
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2 answers
67 views

IV curve has non zero current in open circuit condition

I have an IV measurement program running in LabVIEW, where I measure the IV curve of a photovoltaic module using a programmable electronic load from a quick backward sweep (from Voc to Isc.) I have a ...
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Vernier TDC: how to adjust every stage time differential to achieve 1 TLSB?

How do we get td1 - td2 = 2ns? I have no idea about how to adjust delay cell.
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Query regarding MAX20480DATEJ/VY+ voltage monitor

I'm using a MAX20480DATEJ/VY+ voltage monitor for my design. Out of four inputs, I prefer to set IN1 2.5V at the same time for testing purposes. When I'm running my command, I'm constantly getting a ...
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1 answer
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Connecting an Arduino to both panel and load side of charge controller, can this work?

I just joined this site because my searches haven't turned up an answer to this question, so apologies in advance if I missed something. I have an Arduino powered by the load side of a 12V solar ...
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Does this method of determining what a voltmeter will read in the presence of a time-varying magnetic field give the correct answer?

In a previous answer I offered a method for calculating a quantitative result for what a voltmeter will read when a time-varying magnetic field may be affecting the circuit and/or leads of the ...
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90 views

Battery Monitoring Card Negative Voltage Measurement

I'm struggling to understand the working principle of these negative voltage measurement circuits. They are part of the battery monitoring card. Schematic: Upper schematics belongs to NXP RD9Z1-...
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105 views

Ideal diode for 0-5V range for measurement circuit

I am building a measurement circuit that measures the voltage/current from a thermogenerator. The expected measurement range (and therefore input voltage range) is 0-5V. I plan to measure it with a ...
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