Questions tagged [accuracy]

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Reducing errors in 3-wire PT100 RTD measurement using a Keysight 34461A DMM

I have a 3-wire PT100 RTD with 1.5 m long cables, which I want to measure with a Keysight 34461A DMM. This DMM has a temperature measurement mode for use with RTDs. Aside from bundled probes, I have ...
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60 views

Fluctuating ADC results - is it normal and characterized in a datasheet?

As I have been reading [1], there exist four different DAC error types, which contribute to the overall error: Offset Error Gain Error INL Error DNL Error Is my understanding correct, that these are ...
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50 views

high accuracy analog differential signal switching solutions to prevent distortion (relays?)

first let me define the application and circuit. the application of this is to sence currents ranging from 1nA to around 900mA. to accomplish this two resistors are used, a 10K for the nA range, and a ...
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2answers
81 views

Poor man's voltage reference

I want to build a voltage reference based on LM4040 (A series 0.1%), the output voltage is switchable with a selector switch: simulate this circuit – Schematic created using CircuitLab ...
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1answer
43 views

Use of ADC Bits below noise floor

I have a Sigma Delta Modulator with a SINC3 Filter. The System runs at maximum oversampling possible for this application and I know my (Full Scale Signal)ENOB for this szenario to be 14. Is there ...
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44 views

Why is there a discrepancy in the E192 series? [duplicate]

For all series from E48 through E192, this holds true: $$ value = 10^{\frac i n} $$ where i is the zero-based index in the series and n is the length of the series. The one exception is E192[185]: $...
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4answers
374 views

Confused with the effect number of decimals at the output of transducer

There is an ultrasonic device which measures and outputs both wind speed and direction and has a very long manual. But to keep it short and summarize, the accuracy and the resolution for the wind ...
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1answer
34 views

How to relate the sampling frequency to the measurement error for this kind of pulse period measurements?

I sample a zero to 400Hz varying pulse train at 4kHz and post-process this pulse train data by MATLAB to obtain each single pulse's period. So for instance below represents a 0 to 6V pulse. The green ...
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3answers
82 views

measurement errors: add up or cancel out?

Take an accelerometer, or a hall sensor, or a thermometer, or any sensor. It will have an accuracy, which means the readings will contain some error of this sort. My guess is that by taking a big ...
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1answer
39 views

Calculate measurement accuracy of voltage divider with suppressor diode?

I have a voltage divider to measure the voltage in a DC Bus. I parallel to R1 I have a suppressor diode (D1) to protect the input of the microcontroller from transient overvoltages. This diode has a ...
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1answer
43 views

DC motor accuracy with encoder

I am building a coil winding machine and I've already set up something that works. I used two nema17 stepper motors and tb6600 stepper driver cards. The problem is that motors are seems to overheating ...
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1answer
128 views

Set the Gain of an Opamp Accurately Using a Potentiometer

I want to set the gain of an opamp accurately using an potentiometer, with low thermal drift and good long-term stability. From what I've read, there are three basic ways of doing it, but none of them ...
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124 views

PPS Timer on STM32

The MCU used is a STM32F042 which is clocked by an OCXO oscillator (Abracon 10 MHz - 20 ppb). The subject of this thread is to get the best accuracy on one PPS Timer. For my application, I need to ...
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3answers
93 views

GPS relative positioning

I have a set of 4 rovers crawling on the ground, each of them equipped with a standard GPS positioning system. The rovers start together from a known position. Each rover is locating itself via GPS. ...
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1answer
577 views

Why is my 10k NTC thermistor on average accurate to 2C

I am trying to figure out what is causing the 2C inaccuracy in my thermistor calibrations, my goal is to get my accuracy down to > .1C. I am using the KS103J2 10K NTC thermistor. To calibrate my ...
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1answer
37 views

Finding out the accuracy of the current probe's measurement

As part of power supply testing we are measuring the current profiles of various regulators. Startup profiles includes current bursts with different current amplitudes and widths. i want to ...
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2answers
132 views

Question about the accuracy of integrated resistors

I'm studying the implementation of resistors in integrated technology. In particular the books deals with the accuracy of the obtained resistors. It says: Then it says: "We observe that the value of ...
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1answer
117 views

Load cell accuracy: rated output vs. full scale

I'm currently shopping for some subminature load cells for a research project. I've narrowed it down to two options, the FUTEK LCM100 and the Burster Model 8417. Problem is the two specify their ...
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1answer
386 views

Measure sensitivity of ADC

I would like to benchmark my ADC. I can calculate a sensitivity value based on the information in the datasheet. However, I would like to measure/benchmark this figure. Is there a standard method ...
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6answers
1k views

Would reducing the reference voltage of an ADC have any effect on accuracy?

Regarding the following information taken from a paper: The paragraph is telling about what happens when the ADC Vref is reduced. There is the statement from the above quote: Note that if you ...
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2answers
1k views

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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1answer
38 views

Resistance measurement and standard uncertainty

In a text there is a section regarding a basic example for uncertainty calculation of a resistor. Here is the related part: Above the text uses the the accuracy of the current source and the ...
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2answers
333 views

How accurate are flex sensors?

So for the project I am working on I plan on measuring very precise changes in angle, possibly up to 5 degrees of accuracy. Are polymer ink sensors (the classic Nintendo power glove flex sensor) the ...
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2answers
78 views

Problem understanding impedance measurement device accuracy format

I am reading the datasheet of an impedance measurement device. Its accuracy is listed as '±0.4% rdg. ±8 dgt.'. What does 'rdg.' and 'dgt.' mean? And how should I interpret the accuracy? The device is ...
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1answer
184 views

How can I make my measurements of full-wave rectified AC using an A/D match a Fluke meter on its DC range?

I am trying to measure the DC voltage of a full-wave rectified 60Hz AC signal using an A/D and have it match what a Fluke meter reads on its DC scale. My current approach is to take as many (16 bit) ...
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1answer
95 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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1answer
126 views

GPS L5C Differential? Max Update Rate(bits/s|Hz)?

The differential GPS chips use L1 and L2C to calculate the ionospheric interference. With the new GPS satellites, the new band L5C is being deployed, and I am wondering about the following things: ...
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1answer
152 views

PWM nonlinearity

simulate this circuit – Schematic created using CircuitLab I am using the PIC16F1786 in a current transducer to measure 0-1 Amp DC. I use an A/D converter to measure voltage from a Hall Effect ...
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2answers
59 views

Confusion about the meaning a parameter

Below is a part from this accelerometer: For +/-2g the Scale factor tolerance is given as 10mg. There is also 0.25%. This is in parentheses as 1.25(0.25%) V/g. Is 10mg derived from 1.25(0.25%) V/g? ...
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1answer
58 views

passive probes and accurate measurements

I have read somewhere that if we have a 100 MHz oscilliscope then we can measure only the waveform of 10 MHz accuratley with an error of 1%. My question is that if passive probes are used then will ...
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2answers
301 views

Sigma Delta ADC vs SAR ADC, for multiplexing signal

We are using PIC32MZ series Microcontrollers for our energy based application where we are measuring voltage and current for electric consumers. One single meter can monitor current for upto 10 ...
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2answers
397 views

Confusion about accuracy vs tolerance of an operating resistor

Let's say I bought a 100 Ohm resistor from a manufacturer with a tolerance of 10%. What I understand from the term tolerance here is that: it is the amount that a resistor may initially vary from its "...
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1answer
321 views

Understanding Pressure MEMS Technical Information (Relative and Absolute Accuracy)

In my research, I use smartphones pressure sensor data, and I need to understand their errors and limitations. I found the technical chart for the sensor: But I don't really understand the meaning of ...
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3answers
834 views

More accuracy from analog multiplication?

Let's say I want to detect a voltage signal that's guaranteed to be between 0V and 1V through an ADC whose upper range is 5V. I can hook the signal up to the ADC directly, but then I'll only be using ...
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1answer
110 views

Real time clock MCP7940N I2C interface

The RTC MCP7940N is used in the system. The microcontroller and RTC MCP7940N are connected through the I2C interface. I would to know what is the better design to read the timer value from the RTC. ...
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4answers
2k views

Accuracy of a multimeter over 10 years period

Datasheets of multimeters contain accuracy specifications. One parameter is usually accuracy over period of 1 year. I understand that it means multimeter can be off by the specified value. For ...
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1answer
137 views

How can we achieve position accuracy with simple worm gear box. [closed]

I am also proposing to use simple 40:1 ratio worm gear box with Input servo motor. I am having a dial of 1600mm diameter on output of the gear box which will rotate only in clockwise direction at max ...
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1answer
134 views

How to calculate 50Hz active power measurement accuracy from datasheet?

The R&S HMC8015 power analyzer datasheet and technical data list: Range configuration ...
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3answers
84 views

What are the advantages of a internal high-precision oscilator over an external one

Many lab measurement equipment for analog, radiou and RF purposes, such as frequency counters, arbitrary signal generators, oscilloscopes, etc. have the option to input an external reference clock (...
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1answer
171 views

Increase accuracy of ADC without device AGND

I am using the ADC of the PIC16F18344 — http://www.microchip.com/wwwproducts/en/PIC16F18344 It has neither Avdd nor Agnd, but it does have selectable Vref+ and Vref- pins. If I were to stop using ...
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1answer
193 views

resistor array matched accuracy

I need 4 accurately matched resistors for my circuit, I heard resistor arrays have better matching quality. but I don't know what parameter to look for in the datasheets. all I see is Tolerance. I don'...
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2answers
62 views

what parameter should be noticed in design sample and hold circuit?

if I want to sample from a pulse with 50kHz frequency, that changing between -5 and +5 Volt, what parameter should be considered in choosing op amp to get high accuracy, and How should I calculate my ...
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1answer
2k views

How to have an accurace ADC?(STM32)

Today I was reading the datasheet and refrence manual of STM32. As others, I think we should use the power creativeness which god has gifted us to have an accurace ADC. :) Here are the datasheet and ...
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1answer
60 views

What kind of information can be assumed from sensor accuracy graph

I'm using a MS5803-15BA (datasheet) to make pressure measurements. The datasheet contains this graph of pressure error vs. pressure at page 17. The datasheet also specifies on page 1 that the ...
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2answers
312 views

Necessary Read Frequency vs PPR of Rotary Encoder

I am working on a microcontroller (ATMega328) project where I am planning to use a rotary encoder. I plan to have a non-time critical main loop and set up a timer interrupt to handle reading the ...
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2answers
2k views

Accuracy error of ammeter from specification : is it really just a constant offset?

On ammeter specifications it is often written accuracy specification $$ (....\% rdg+ ... digits) $$ While the ammeter can have a certain last digit on the screen, which determine the resolution if ...
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1answer
2k views

DC motor RPM accuracy/precision

Small, permanent magnet, brushed tri-phase DC motors ('toy motors') may give a speed/torque curve, or at minimum a no load RPM. What is typical RPM accuracy relative to the datasheet, and how precise ...
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232 views

unstable magnetometer readings

I did the magnetic calibration here on the LSM303DLHC for a field roughly 48 uT. The method seems to have worked in that the combined bias (b) values went from ...
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2answers
669 views

Accuracy of various elements in circuit

Every op-amp has error. We all know that. So logically, the more op-amp used, the less accuracy we will have, right? In the circuit ,there are 2 parts: first is the current to voltage converter, ...
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1answer
90 views

Component manufacturing and placement accuracy/precision

I am involved in a community project where I need to employ computer vision on common smartphone models (Samsung Galaxy S 5/6/7, iPhones etc.). Doing that involves calibrating the phone's camera for ...