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Questions tagged [measurement]

Measurement is the assignment of numbers to objects or events. All measurements consist of three parts: magnitude, dimensions (units) and uncertainty.

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WIll the multimeter continuity test on the SOIC - DIP adapter spoil my IC?

IC : L9637D for ISO 9141 bi directional serial comm. Multimeter: Mastech I am mounting an SOIC 8 IC on an adapter(regular Soic to dip adapter), so I can mount the adapter on a bread board for use. ...
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22 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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7 views

Hspice : find max of measurement result in Hspice

i need to calculate efficiency of a circuit for diffrent parameters and then, find MAX of these efficiencies in Hspice.( also related parameters that refers to it) i ran i .DATA transient simulation,...
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1answer
53 views

Reading digital wafevorms via VXI11 from the LeCroy wavesurfer 510/MS-500

I automating a test with an osciloscope via VXI11 with python's vxi11 package. I am using the remote control manual given by LeCroy. I am trying now to extract the raw Waveformdata according to page ...
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1answer
41 views

Correct way to ground components for solar panel measurement

I'm currently doing a project where I'm supposed to measure the current and the voltage from a solar panel and am unsure of how I should ground all the components in the circuit (since electrical ...
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61 views

Photodiode to detect light

For a university purpose I am preparing a project, actually I am thinking of using a photodiode in reverse bias in order to measure intensity of light. I divided this project in some phases: 1) ...
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1k views

Detect and measure fog outdoors

Currently working on a project requiring me to detect fog, and measure the amount of fog. It doesn't have to be accurate but it has to give a sense of how foggy it is. The device (probably Raspberry ...
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89 views

Mistake in reading a rms voltage

I got a really strange result. I've build a full-bridge rectifier with a capacitor filter. And I used the following values \$\text{C}=500\cdot10^{-6}\$ and as a load \$\text{R}=1000\$. The maximum ...
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1answer
54 views

Measuring integrated current

I want to measure the amount of light striking a photodiode in a specific time window (about 1ms). In this window, we get \$10^6-10^7\$ photons, which get converted into electrons with about 80% ...
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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
90 views

S-parameter measurement of thin polymer film

I need to obtain S11 and S21 to calculate loss tangent of polymer(PVDF) in C-band. I have an access to vector network analyzer, to use it I must somehow attach 2 SMA connectors to polymer and here ...
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1answer
304 views

Measuring a varying capacitance using the Wien bridge

I am going to make a capacitive soil moisture sensor. The principal that I'm going to use is the change of capacitance of the soil with moisture. What I'm going to do is make a capacitor that would be ...
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843 views

ADC and internal noise

I have a question regarding AD conversion in a microcontroller. Before we go on, I use a dsPIC33EP64GS506 (link on its datasheet), 3.3 V power supply, and 12-bit ...
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24 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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1answer
49 views

What is the correct name of a job involving mainly programming measurement instruments and making measurements on electronic components? [closed]

While revisioning my resume I found out that I do not know what is the industry standard name of one of my previous job. I simply called it "Software developer" but I don't think it fits properly. ...
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30k views

What color is positive on a multimeter?

I bought a multimeter with attached leads. I would think red is positive but when I take a reading it only works if I use black as positive. Was it assembled wrong? There's nothing in the manual. It's ...
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1answer
57 views

Impedance/capacitance measurements

I'm trying to do some impedance measurements on passive components with the simple circuit shown below. I find it difficult to make sense of the results and hope somebody can help me understand what I'...
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2answers
394 views

How does this current sensor work (with only half magnetic core)?

I have been working for sometime with current sensors (current sensor goes all around the conductor to get a voltage reference corresponding to the amperage), however I just found this little device ...
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1answer
55 views

What's the right kind of reference to calibrate a measurement instrument?

I have been working in a calibration system for a multimeter I'm developing. To do this I'm calibrating the reading values using Fluke meters (basically my instrument has to match the Fluke ones). ...
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2answers
2k views

Sensors to detect and measure movement

I would like to know which sensors should I use in order to get measurement of a movement of my device (slow speed movement on a 2D plane, in cm or mm if possible). The goal is to find out if the user ...
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1answer
65 views

High PWM frequency weird shape

Using a STM32F407 if I generate a 200 Hz signal it looks like this: If I want a higher frequency, for instance 10 kHz I get this: I am using a PicoScope 2205A, resolution 8 bits at 200Ms/s, ...
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92 views

How to take resistance reading when value is effected by measurement?

Context I am trying to measure the wiper resistance of a potentiometer. This is performed by leaving the potentiometer wiper in one position, and measuring from each terminal to the wiper (\$R_1\$ ...
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106 views

Probes gives different results

I discovered an "funny" thing today. I had used a GW instek probe GTP-150B-4 150Mhz in 10x mode and documented the result. Today I noticed in the testing department that what I've measured doesn't ...
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1answer
33 views

Measure pulse width generated in one pulse mode using HAL

I need to generate pulse in one pulse mode and measure width of this pulse using HAL. I'm using STM32F446RE board. I managed to configure timer to generate pulse but I have no idea how to implement ...
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4answers
3k views

How to measure the temperature of a thin wire using a infrared (IR) thermometer?

I got a laser thermometer to measure the temperature of a wire for my science fair. However, when I attempted to measure the wire, it was too thin and I just measured whatever was behind it. How can I ...
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3k views

Which one is more accurate: Digital oscilloscope or Analog oscilloscope?

I know it is some sort of wide question, but nowday I usually only see digital oscilloscopes around. I want to know if their digital nature will affect the accuracy of measurements? (Something like ...
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1answer
126 views

How to estimate displacement error using accelerometer

I am using an MPU6050 and performing a double integration to obtain displacement, and this is to be placed in a vehicle that will be subject to about 2.5g. I cannot test it now, but how is it possible ...
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127 views

Is there any way to noninvasively/invasively measure the current/voltage (Power) to get actual power consumed by load?

One of the application im working on needs three phase power measurement to be done through micro-controller. The power measurement is in the range of 90kVA. Is there any way to noninvasively/...
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3answers
3k views

Precision Power Supply / Elektor, December, 1982

Since this PSU was published by Elektor I assume that some of you might heard or read about this project. http://www.retro.co.za/zs1ke/projects/PrecisionPowerSupply/PrecisionPSU-Elektor-Dec-1982.pdf ...
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155 views

How do induction cookers measure temperature?

This is not exactly about electrical circuitry, but I hope it's close enough not to get me kicked out. Please redirect me if necessary. Almost all induction tops advertise possibility to "keep ...
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0answers
81 views

Wrong measurement of DSO-5200A?

I'm using a DSO-5200A from Voltcraft and noticed the voltage measurement represented incorrectly (it is doubled). Any ideas how to reset this? Channel 1 (green) measures a (noisy) 5V and has a Vmean ...
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4answers
492 views

Converting ADC output to real values [closed]

On a custom board I have an ADC which measures -5V to +5V. And outputs in Hex via SPI like this: ...
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1answer
107 views

What's the difference between measurement resolution and digits per second in time measuring devices

In time/frequency counters/analyzers in technical specifications you can almost always find resolution and digits per second values next to each other. What is the difference?
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How to eliminate oscilloscope channel DC bias

When I set channel 1 as DC coupling, there is always -5.6v bias, even no cable is connected. Can someone tell me how can I eliminate this bias? Thank you
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2answers
2k views

Determining state-of-charge of a lead acid battery under load

I am trying to implement an extremely simple lead acid battery state-of-charge (SOC) estimation calculation. The following values are known: \$V_F\$ for SOC=100%: Open circuit voltage of the battery ...
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3answers
104 views

Sensors to detect vehicle height from the side

I am looking for a way to determine vehicle height measured from the side. The application is for a drive-through ATM, the sensors being mounted inside the ATM enclosure. Some ATMs have a roof as ...
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1answer
149 views

Calculation of active power and apparent power through sampling

I'm currently working on a power meter device based on simultaneous sampling of current and voltage values, I intend to use this system to measure the active, reactive and apparent power on a non-...
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2answers
95 views

Count car weels without using visible light (camera/laser etc) and without interaction [closed]

For this project we need to count weels of a car (if possible at all), one side only. The scenario is within the following scope: The car is always passing in a straight line It is cars only, so all ...
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48 views

Amplifying pulse signals causing pulse lengthening problems

I am currently trying to design a circuit that would sense a voltage change at its input, convert that change into rapid "on"/"off" change at output and amplify same switching voltage to high current (...
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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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1answer
64 views

How to measure the impedance of a given coil? [duplicate]

What's the best way to measure the resistance and inductance of a coil at a given frequency? I need these parameters for my LTSpice-Simulation which assumes an RL series circuit. The coil has 8 ...
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4answers
11k views

Digital bathroom scale circuit - how it works?

I'd like to understand how the digital bathroom scales work. I was able to gather that there are four three-wire load cells connected into the Wheatstone bridge as suggested below. The load cells have ...
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4answers
3k views

Big capacitors measurement(LCR meter related)

I digged up some capacitors from amplifier and decided to test them, one of them is said to be 8200 uF, the other 4700 uF. I measured them with LCR meter and it gives very strange numbers. If LCR ...
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3answers
1k views

Methods to measure inductance with high (1%) precision using standard equipment?

I am modeling the fine behavior of interacting oscillatory circuits. I have looked up a couple of methods for measuring inductance. I believe I am following the procedure faithfully, but the values I ...
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3answers
5k views

Measuring transistor beta (hFE) - Ib anomalies explanation needed

I've been struggling with details of building accurate (\$\pm1\%\$ tolerance maximum) beta meter. The simplest idea I came with went to a diagram as shown below, with R set to a value providing a \$0....
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4answers
1k views

Why do LCR meter manufacturers give the details of measurement frequency to us?

When you want to purchase a DMM, more probably you don't see at what frequency the DMM you considered would work, but in the situation you're considering to purchase an LCR meter, manufacturers give ...
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30 views

Can I use a RF and/or Time-domain reflectometer to find 'wet contact'?

Friends of mine have a circuit where the RCD trips but only after prolonged rain. There are a number of garden and security lights on that circuit so I very much suspect there is a junction box where ...
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2answers
103 views

How isolation is achieved in isolated channel oscilloscopes?

I tried to search something about this but found only a small amount of information. What confuses me is that all isolation amplifiers, optocouplers etc. I could find usually work at much lower ...
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84 views

Darlington Transistor TIP142 same type but different values

I have a bunch of Darlington NPN Transistors TIP142 that are removed from two separate identical boards. The 1st one have the TO−218 CASE (left side of the image) and the 2nd the TO−247 CASE (right ...