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Questions tagged [voltage-measurement]

Act of measuring voltage

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1answer
62 views

Invert Voltage 0-2V

I need to invert voltage from the one sensor. So the ting is that I have DC signal from sensor: 0%-100% range of 0V-2V I need: 0%-100% range of 2V-0V I have LM324 level indicator and it is showing ...
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0answers
56 views

Multimeter keeps increasing wrong values [on hold]

I have a Dynatek 110 Multimeter(Digital). It kept showing wrong values; I decided to replace the battery which had passed its expiry date by appr. 18 years. Unfortunately it didnt make any difference. ...
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0answers
15 views

Clarke transformation for delta wiring

I find the transform to get alpha,beta and zero for Y wiring(image below), but didn`t find the transformation for delta wiring(Vab,Vbc,Vca). Someone know the tranformation for delta case?
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58 views

Help simply the resistor usage in this voltage summer and divider circuit

Can someone help simplify the resistor usage in this circuit? VS is a constant 5v supply. Flex is a variable voltage between 0 and 5v. The resistors above have been brute forced to achieve this ...
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2answers
57 views

Is it possible to lower an ADCs input range?

I'm trying to use an ADS8504, a 12-bit ADC, and get as good a resolution as possible. The ADC accepts inputs in the range of +-10V. However, my circuit is limited to only having a power supply of 5V ...
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0answers
22 views

Can LM3914 be set up to work as an exclamation point and alarm flasher with a symmetrical input?

As the title implies I'm trying to make LM3914 to work as an exclamation point and alarm flasher. There is already a set up how to achieve both individually in the documentation from the LED bar ...
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2answers
34 views

Question on brushed DC motor voltage measurement

I'm operating a brushed DC motor via PWM at 5 kHz. It's a big motor rated at 125V/27A. I don't have an voltage acquisition circuit. Just a multimeter. But I want my microcontroller to know what the ...
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45 views

Testing function generator with multimeter

I bought a used signal generator today. I want to check if it works with no problem but I don't have access to an oscilloscope right now. I have a multimeter that can measure dc and ac voltage and ...
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51 views

Measurement of high voltage with low voltage circuit

Is it possible to make a high-impedance, precision measurement of a 10V DC signal (dynamic range requirement is only ±1V with a DC-1kHz BW) using amplifiers and an Sigma-Delta ADC supplied only by +3....
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1answer
38 views

Optimization voltage divider measurement

How to design a voltage divider to optimize the measurement error? Intuitively I would take the same ratio $$\frac{load}{divider} = \frac{divider}{measurement}$$ As follow: the voltage is roughly ...
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2answers
25 views

Measuring battery voltage in PV scenario with MPPT charge controller with inverter

So I'm doing a PV project with wifi enabled statistics. I'd like to see the watts coming in and out and the battery charge level, estimated battery charge and discharge time. I'm designing PCB to ...
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2answers
75 views

My multimeter probes are too big to measure a laptop battery

I'm having laptop battery problems, and the hardware manual gave diagnostic instructions involving measuring the voltage in the battery. So I bought a multimeter (never used one before in my life) and ...
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0answers
22 views

toggling current mirror circuit

I am designing a circuit to sample the voltage from different battery cells that are serially connected (for a Battery Management System). The whole point is to measure the voltage of each battery ...
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1answer
37 views

Multimeter temperature coefficient - Specified accuracy

I want to calculate the temperature coefficient for a digital multimeter. The datasheet I read it is calculated as: 0.1*(specified accuracy)/°C (<18°C or >28°C) Do you know what specified ...
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2answers
74 views

Voltage sense multi range - how to switch with no voltage drop

I have an application where I need to measure precisely (<0.05%) a voltage level which can be from 1V up to 500V. To do so, I use several voltage divider that are then multiplexed to a ADC. ...
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0answers
23 views

Measuring a magnetic field using a loop

I am trying to use a loop to measure oscillating and pulsing magnetic fields. Using Faraday's Law (N - number of coil turns, B - magnetic field, A - area of coil, t - time) I should be able to ...
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54 views

Flyback Transformer Output Voltage Testing

Recently, I purchased an electrostatic precipitator power supply as a means of providing a high voltage DC output (-5 - -40 kV DC). The power supply is rated to supply 60 kV DC at 600 W and can be ...
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2answers
76 views

Protecting against over voltage but with minimum leakage current

I have a circuit where I sense an input which is a voltage divider with resistor. Since the voltage divider needs to have high impedance, the current flowing through is in the range of 10's of uA. I ...
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5answers
105 views

What kind of tool is used to record a voltage over time to a PC file like a waveform?

I don't have any training but am doing some hobby electronics. I would like to record a change in voltage over time, sampled at around 100+ kHz. Ideally, I'd like to record around 20-30 min of two ...
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2answers
34 views

Measuring floating gate potential with minimal leakage current

I am working on a sensing device where the voltage of a floating node is dependent on the quantity to be sensed, as well as the net charge stored in the node. I would like the device to be only ...
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1answer
34 views

Can I add an INA219 voltage\current sensor to this USB powerbank?

I have a Raspberry Pi Zero in a small robot that I have been powering off a USB powerbank and it works great. Unfortunately when the USB battery goes flat the power is cut and the Pi crashes. I want ...
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4answers
1k views

Measuring AC voltage without a transformer using a microcontroller

As I have no practice with AC voltages, I'm asking if the following circuit is reliable for measuring AC voltages about 110Vca and 220Vca 50Hz/60Hz. I have already made it with a small transformer. ...
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1answer
50 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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1answer
42 views

Is it appropriate to use a 300V RMS CAT I rated oscilloscope to measure 230V RMS of a power inverter?

Yesterday I decided to look at the waveform of my portable power inverter. The inverter specs are the following: Input: 12 V DC Output: 230 V RMS Rated power: 300 W I powered my inverter from a ...
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4answers
45 views

Measuring SuperCap current leakage avoiding voltages drops in ADC

I have a circuit with a SuperCap used as a battery. I want to know the curve of SC voltage in time to finnaly measure its self-discharge. Is this can be done with a simple arduino or another ...
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1answer
89 views

How to determine DC input voltage of a device without its charger? [closed]

Had a MotoMaster (Canadian Tire) 27/3 LED flashlight for 4 years now. Model was discontinued 2-3 years ago. Lost the charger at least 2 years ago and the light's battery FINALLY died today (!!) I ...
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1answer
157 views

INA219 measure voltage of battery with RPi

simulate this circuit – Schematic created using CircuitLab I want to measure voltage of 12V battery powering something by INA219 connected parallel to this battery and read it with RPi via I2C. ...
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1answer
60 views

Is there some way to measure mains voltage with the ACS712 sensor?

Last year I went to a maker event where some guys used an ACS712 sensor with an Arduino to monitor the mains voltage and current to monitor the energy cost in the house. One thing I saw there is that ...
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2answers
166 views

Why do I measure (almost) no voltage between 230V phase and my body?

The other day I was experimenting with a multimeter and checked the voltage in one of the electric plug at home. Without surprise I measured around 230V between phase and neutral and also 230V between ...
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0answers
66 views

Advantages and disadvantages of voltage output vs. current output PMT modules

Context: I am building a custom right-angle static light scattering setup to measure aggregation of biomolecules in aqueous solution. I need the instrument to be as sensitive as possible, to allow ...
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2answers
91 views

How come no voltage is meassured across my electrolysis tank?

I've built myself a electrolysis tank, using a plastic barrel as the container, rebar as the sacrificial cathode, a 12v 15A car charger (DC), and a Sodium Carbonate solutions as the eletrolyte. The ...
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1answer
87 views

Measuring 200 volts safely

While I can measure line voltage safely, I need to write a procedure to have someone else measure the voltage. The load is pure resistive,and I want to measure the voltage across it, with a battery ...
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0answers
39 views

Trouble with biased measurement for Oxygen Sensor EC410

I need to achieve a -600mV bias between Vsense and Vref for a potentiostat circuit. I'm trying to replicate the design for an Oxygen Sensor (EC410) by following the above image from the application ...
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2answers
90 views

Ground loop via pull-down resistor

I'm developing an STM32-based device, one of whose functions is to periodically monitor the main power 12V battery voltage. I created a simple switching circuit with a voltage divider. I have added a ...
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0answers
32 views

Measuring small strain with strain gauge, how nullify errors?

I have a similar circuit like https://www.egr.msu.edu/classes/ece480/capstone/spring15/group05/uploads/4/7/5/1/47515639/ece_480_app_note_justin_bauer.pdf 2. page bottom Wheatstone bridge: 2x 350 ohm ...
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1answer
47 views

in-amp for strain gauge

I'm working on a project where I should send an overload signal if the strain is bigger than 40 ppm. So far I found this answer: Strategy to balance a Wheatstone bridge for strain measurement The ...
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1answer
43 views

Can one voltage output from OpAmp read with two ADC inputs?

this might be a little silly question, but please advise me. I am trying to use two photodiodes (one for the absorbance measurement and one for the source of the light as a reference) and the voltage ...
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0answers
20 views

Topological observibility in OPP problem

I have a short question about observability analyzing constraint in optimal PMU placement problem in power system. Observability analyzing has two method: numerical and topological. Most of papers use ...
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0answers
49 views

Rectified X2 circuit gives 2 voltages depending on how the powerplug is connected to the wall (EU)

simulate this circuit – Schematic created using CircuitLab I'm trying to control a mosfet directly from a phase shifted 50Hz sine wave. But when I was trying to understand the voltage drop with ...
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0answers
24 views

LTspice modelling for the end terminal side

So I have this model. I am trying to build a current/voltage converter circuit for a bus carrying current to the other end of the bus, because I need to give this voltage output from the amplifier to ...
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0answers
97 views

Step up transformer protection

simulate this circuit – Schematic created using CircuitLab Hello, i have question regarding the short circuit current at both primary and secondary side of the XFMR2. Given the values in the ...
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2answers
108 views

Measuring crystal drive strength without a current probe

TL;DR Is there a means of measuring the crystal drive level reliably using voltage measurements (even with a differential voltage probe)? Background: I am attempting to measure the crystal drive ...
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0answers
117 views

Non contact voltage tester

I built myself a very simple non contact voltage tester with a couple of transistors, an LED and a wire at the end to work as an "antena" like the picture demonstrates: It's for a school project and ...
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2answers
487 views

How to measure output voltage and current of a VFD?

Is it possible to measure the output of a Variable Frequency Drive without relying on it's display data? I tried to measure the line voltage with a DMM and current with a clamp meter but it shows ...
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1answer
55 views

circuit for mesure positive & negative voltage + Vref resolution

i would like to make a "voltmeter" to read from +2V to -2V and connect it to an Arduino ADC ( 0V to 5V ). I found different configurations for do this job: From this site: Bipolar to unipolar ...
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1answer
136 views

Can I use a twisted pair for 5V and ground?

I'm going to use a RS485 modbus connection which requires a twisted pair. Now I also need power, that will be a 5V line and a ground. The distance will be about 3 meters max. Can i use a twisted pair ...
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1answer
33 views

Avoiding accidental earthing, voltage rejection, and voltage dividers for a motor control output circuit

I'm trying to connect up an integrated control DC motor with a 24V output (Motor manual - relevant page p32) with my 10V PLC (PLC Manual), and looking for a little help please. I don't understand why ...
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1answer
56 views

Whats the equation to calculate the Vo-w and Vp amplitude of this Wien Bridge oscillator?

Im trying to find the equation to the amplitude of this wien bridge, if you could help me that would be awesome
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1answer
88 views

Problem with mesuring value from current sensig pin on VNH2SP30

I connected the Monster Motor Shield (based on the VNH2SP30) to the Arduino Uno and successfully drive the engine, but I can not measure the value from the CS pin on this board (the voltage at this ...
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0answers
61 views

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 ...