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Questions tagged [voltage-measurement]

Act of measuring voltage

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Drift in high resolution temperature measurement

For a calorimetry project, a precision temperature measurement (0.001 K resolution in the range of 15-25 °C) is required. Note that the absolute temperature accuracy is secondary, crucial is the ...
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0answers
35 views

Precise current and voltage measurement

I do current and voltage measurement at the same time with a low side ayrton shunt resistor network and a high side voltage divider. I want to measure voltages up to 400V positive or negative. The ...
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Convert raw data recorded in python with sound card (ADC) to input voltage Vin

I am trying to convert the ADC output code recorded using the sounddevice module in python back to its physical voltage quantity, i.e trying to calculate Vin in my sound card's input. I am using a ...
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1answer
67 views

Hardware specification terminology

I have a hardware specification document of a product attached below. I am able to understand the following parameters: Input voltage - This is defined for the range of input voltage Resolution - ...
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40 views

Isolated Voltage Measurement

In my application I need to measure a voltage that is in the area of 50V, but my microcontroller has to be isolated from my power circuit. I came across the ACPL-C87A-000E IC. I followed the typical ...
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4answers
883 views

Is it possible to measure lightning discharges as Nikola Tesla? [closed]

Nikola Tesla stated in his patent, Art of Transmitting Electrical Energy Through Natural Medium, that he used sensitive instruments to measure lightning discharges: In the course of certain ...
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2answers
51 views

AC Voltage: Wild Reading: phase-neutral & neutral-ground (240V/120V)

I'm getting some unexpected readings when testing a circuit for my wall mounted AC&heat. I'm on standard USA 120V/240V split-phase/three-wire AC power; the specific circuit is 240V. here's a ...
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2answers
63 views

Real-time measurement of motors' current draw for a mobile robot

Found an Arduino-compatible Voltage-Current Sensor; it could remove the need for a separate voltage sensor. Is there a more recommended method to continuously and simultaneously measure the current-...
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61 views

1st KiCad design. Concerns with an abnormal circuit

I just wanted some input before sending this off for manufacture. It is for a test fixture and just has a funny circuit. Even though it seems relatively straight forward, it took a bit of finagling. ...
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1answer
69 views

Dynamic voltage divider

I'm trying to build an ESC (electronic speed controller) for three phase brushless motor. I found some intresting circuits but I am trying to build something very easy to do, with mosfet and pc817 and ...
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4answers
90 views

Voltage error when connecting a zener diode

I am working on a project where i need to measure the battery voltage and send the measurement to a uC, which is powered by 3.3V. The voltage divider is projected as shown before: As input we have ...
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27 views

Correcting DC offset in op-amp based controlled current source

In an attempt to develop an automated potentiometer measuring device I have implemented the following op-amp based voltage controlled current source, controlled by the output of a DAC. The voltage ...
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52 views

Individual Three Phase Potential Transformers vs Three Potential Transformers in one case

If I had to select between Individual Three Phase Potential Transformers vs Three Potential Transformers in one case for a 600V system (which doesn't require many inches of spacing between phases to ...
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26 views

check remaining charge of 28V 5Ah Li-ion battery via ESP32

I'm currently doing a project where I have to power some LEDs from a battery remotely. It's done with an ESP32 and the whole system is powered by a 28V 5Ah Li-ion battery. I am using a DCDC-Converter ...
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3answers
167 views

Why doesn't this battery voltage measurement circuit work? [closed]

So, I built this simple circuit for measuring voltage from a battery pack to an Arduino. The thing is, I want to measure the first cell and then the voltage from the whole battery pack: using two ...
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1answer
50 views

How to receive 40V-DC to 100V-DC range analog output into 9V-DC to 24V-DC analog input?

I am software guy and this is my first time here. So pardon me for my lack of understanding. I have a device with analog input, that can read analog input in the form of DC Voltage within the range ...
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3answers
52 views

Ambiguity in voltage measurement

So I watched this extremely fundamental video about voltage measurement and how it's measured. The one thing that confuses me is what people use a reference for zero potential. The two diagrams shown ...
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48 views

A general math problem that pertains to resistors in AC circuits

I've been reading from this website as a refresher on basic circuits and circuit components. I have no problem understanding the properties of resistors in circuits and how to calculate V, I, or R, ...
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2answers
123 views

Oscilloscope range affecting voltage reading

I am trying to measure the current usage of a device using an oscilloscope. Every second the device turns on for a few milliseconds and then goes back to sleep. I need to find how much current is ...
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21 views

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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60 views

Circuit that averages voltage

Suppose we have an oscillating signal V(t) with V(t) >= 0. I'm looking for a circuit that averages this signal over a given time so that I can read out the average value directly using a simple ...
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1answer
41 views

Voltage drop across buck converter

In my robot, I plan to have a GPIO pin on my Raspberry Pi connected to the insertion detection pin (pin 3) of a barrel jack (schematic here) so that my code can tell when the robot is externally ...
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2answers
74 views

Elimination of interfering voltage

I have a problem deriving a formula I will be using in my bachelor thesis. It's about eliminating interfering voltages during measurement. To understand how the interfering voltage is going to be ...
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3answers
2k views

Determine voltage drop over 10G resistors with cheap multimeter

I have two 10G resistors connected in series with a 3V battery. I want to determine the voltage drop across one of them, which of course is 1.5V. When I use my multimeter to check the voltage drop, it ...
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3answers
329 views

The Ohm's law calculations of the parts do not agree with the whole

In the circuit below, the Ohm's law calculations of the parts do not agree with the whole: the voltage drops of the parts do not add up to the total voltage, and the current does not calculate to be ...
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3answers
82 views

How to measure voltage of each bank in a Marx Generator?

If I have a 10 stage Marx generator with each stage at 2.5kV, when I erect all the stages the last stage's negative terminal will be at 22.5kV with respect to ground. If I want a voltage ...
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2answers
44 views

DC test equipment to see voltage extremes? [closed]

I want to experiment with magnets and coils to produce voltage. I need test equipment to find the highest positive voltages and the lowest negative voltages obtained during tests. My needle driven ...
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53 views

20 kV 100 mA Voltage Current Sensor

like the title says, i need to measure 20 kV 100 mA line. For the voltage part i found this:http://www.koncar-mjt.hr/en/docs/koncarmjtEN/documents/61/1_0/Original.pdf and this:https://www.hivolt.de/...
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3answers
5k views

How do I measure a voltage greater than 5 V with Arduino? [duplicate]

I want to measure a varying voltage with an Arduino and real time data plotting has to be done. But the supply voltage will be 10 V and the Arduino is not supposed to have more than 5 V. Is there a ...
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1answer
47 views

Differences in voltage measurement at the input of a circuit

I am trying to understand the difference I am seeing in voltage signals, that I am applying to my circuit's input. So the basic layout is shown in the diagram, I have a connection, A from my function ...
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3answers
58 views

Power determination for resistive load

I am a mechanical engineering student and i need to measure electrical output. I have some voltage and current measuring instruments. I used them to measure the voltage & current of a blower(...
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0answers
44 views

How to connect photo-transistors to trigger Arduino event

I'm busy doing my finals project, and I need to have 5 photo-transistors come together on the same pin to trigger an event whenever one of these transistors drops it's voltage because an object is ...
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3answers
82 views

Possible reasons for differences in voltage between garage opener circuit and Raspberry Pi

I am attempting to use my Raspberry Pi's GPIO to activate a garage door opener (specifically Craftsman 139.5364812). As far as I can tell, the garage door is operated by shorting two terminal screws ...
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1answer
1k views

Is it normal for a lithium ion battery to read with a very low voltage on a multimeter?

I have a PS Vita and I suspect the battery is dead and needs replacing, as the Vita won't charge at all. But the issue could also be the charge circuit, as when plugging it in to charge the charging ...
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2answers
97 views

Non-intrusive measurement of current and voltage

Sorry if this question is too basic for this forum... I'm an interested amateur but far from a professional. I'd really appreciate information from someone more informed than myself. Hypothetical ...
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3answers
1k views

Measuring a small resistance, ~0.001 ohm

I have a low resistance resistor that I would like to use to measure the current through another circuit, but first I need to accurately determine its resistance. Its data sheet says it is 0.001 ohm +...
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1answer
36 views

What would happen if you measured voltage between power strip GND/neutral an external object?

Probably a totally stupid question but I'm a novice trying to understand fundamentals. If I stuck one multimeter test lead into ground or neutral on a live power strip with some things plugged in, ...
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1answer
317 views

Calculating a voltmeter reading

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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1answer
188 views

Opamp Buffer output voltage offset

I am building a system which will measure and record the voltage of batteries. There are 8 channels in the system with each channel being capable of measuring 0-35V. The accuracy we have decided upon ...
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1answer
27 views

Trying to Build a voltage-driven smart shunt/threshold switch

I'm trying to build a smart DC switch that measures the input voltage (3V to 40V)1 and determines to which output pin to send it, similar to this threshold switch idea or a SIP3242 for Vin, not load ...
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4answers
373 views

Ultracapacitors as a battery; how long will they last?

I would like a formula to be able to calculate how long it would take 6 2.7v 350f ultracapacitors connected in series to degrade from 14.4 volts to 11.5 volts given a parasitic draw of a specific load....
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4answers
87 views

Oscilloscope coupling and effects on the measured signal

I have a basic understanding of the of coupling settings on an oscilloscope, but I need some help to understand what I am seeing on scope. I have a signal generator, with an arbitrary function set, a ...
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2answers
92 views

Voltage readings in Transistor used as switch

I have been trying to understand the operation of transistors for a while now. Today I thought to put what I learnt into test. Cutoff operation of a NPN transistor. As I read in one of the transistor ...
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1answer
96 views

Simple way to avoid current draw on resistor divider sense?

This is a simple, but complicated question. I measure voltage on several lines, more than 3'000. The lines can be up to 100V. I only need to measure at certain time, and would like to avoid current ...
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3answers
283 views

How can I create voltmeter with Zener diodes?

simulate this circuit – Schematic created using CircuitLab 5 LEDS One LED is to remain always on when current is passed through. One LED will turn on when voltage is between 50 to 90 volts. ...
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1answer
48 views

Why is there a minimum input resistance?

I was looking at this multimeter, and it says, Output rate:     0.1 V/A (use with a device having a 1 M-ohm input resistance or higher) Where can I read why this minimum resistance is required? ...
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1answer
136 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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1answer
86 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
68 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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2answers
101 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 ...