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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Is it possible to measure impact force using Flexible PVDF Piezoelectric Film? [on hold]

If it is possible , should i use integrator circuit first to hold the signal then follow it by other signal processing signals (amplification and noise filtering ) ? , knowing that i tried to connect ...
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30 views

Measure precisely a resistance value [duplicate]

Basically, I'm tasked to study the electrical properties of different screws (all in an unspecified titanium alloy, some fully anodized, others only the head) based on previous measurements that ...
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1answer
131 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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1answer
33 views

Best method to determine current in ESR meter

I've recently found the need for a ESR meter(My daughter and her boyfriend brought me 8 broken LED/LCD TVs and 6 have power problems). I also decided to go all out and build a full blown ESR meter. ...
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43 views

What is a suitable hysteresis value and averaging period for a residential thermostat?

I've built a microcontroller based thermostat that I am using to control my home HVAC system. The actual programming and physical assembly has been straightforward. I'm using DS18B20 sensors, so I ...
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2answers
70 views

How can I get FROM and TO times of trig on measure statement of LTSPICE?

I need to measure the voltage on two signals which have a difference of phase, so in order to do the measure that I need I have to get V1 (t) and V2 (t + delay_between_signals). One way to that is by ...
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2answers
66 views

Higher precision with less digits?

Consider an ideal digital milliammeter (zero resistance, zero uncertainty on AD converter input) with realistic (noisy, hysteresic, etc.) AD converter output and a \$3½\$ -digit display. Often when we ...
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1answer
163 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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3answers
122 views

How do digital multimeters measure capacitance?

How do digital mulitimeters (DMM) measure capacitance through their typical 10M Ohm input/output impedance? Providing a logic level of 3.3V, attempting to measure 1F would mean a time constant of ...
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3answers
108 views

How and when does the kelvin measurament actually works?

I know that 4 - wires method uses 2 wires for driving current throught ammeter and measure current values. So, resistivity wires will be removed from the equation. Ammeter wires resistance has no ...
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2answers
47 views

Task Execution time measurement on Keil for STM32F103

Is there any builtin feature available in Keil uVision to measure execution time of a function or task for STM32F103?
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2answers
156 views

VSD (Inverter) current measurement on 3 motor phases

I'm working on a project to build a rig for testing various sized Variable Frequency Drives (VSD's / inverters), the kind that you'd use to run a squirrel cage induction motor. The range would be from ...
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1answer
995 views

Converting negative DC voltage to positive equivalent

Requesting some input on this topic which has already been discussed (partially for my requirement) here: Negative to Positive Voltage Converter I also have a positive-only display and I need to ...
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4answers
2k views

4-terminal shunt resistor [duplicate]

What is the importance of a 4-terminal shunt resistor? What is real purpose behind using two seperate terminal for the voltage measurement across the shunt resistor?
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1answer
49 views

Discrepancy between EMF measures

Why, using a EMF tester on a smartphone in airplane mode, do I get a very low measure (\$< 1 mG\$), whereas using some applications which exploit the phone magnetometer, I get a very high value, ...
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2answers
81 views

Vector Voltmeters vs Oscilloscopes?

I have come across some electronic engineering papers from the mid 1970's where they were testing tunable phase shifters. To measure the phase shift they used a vector voltmeter. As this is not a bit ...
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2answers
49 views

uncertainty estimation for a DMM voltage measurement

My DMM has a accuracy of 0.0030% of reading + 0.0030% of range, when the voltage range is set to 100mV. If a measurement with this DMM gives 0.1mV, then is the true input voltage between 0.1mV - 3....
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3answers
400 views

Practices for using a scope, scope probe and termination resistor for a proper measurement setup

In a setup, assuming a function generator has 50 Ohm output impedance and a coaxial cable has 50 Ohm characteristic impedance. Therefore to prevent reflection of a signal a 50 Ohm termination is used. ...
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2answers
40 views

How I can simply measure interwinding capacitance in a transformer with electrostatic shield

I want to measure which is the effect of the connection of the electrostatic shield (between primary and secondary) to ground (or to neutral) in reducing the interwinding capacitance in my transformer....
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3answers
63 views

RMS power and phase angle control

We have a piece of industrial equipment using a phase angle controller (PAC), and are having some issues calculating the RMS power used by the load. Personally I am of the opinion that you measure ...
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1answer
40 views

Measure Power Consumption of Battery Charger?

I want to ask how to measure power consumption of battery (Li-On 18650) charger module (TP4056 and USB Boost) and the total power consumption, if i have this circuit: I have already know the power ...
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2answers
203 views

Biased single-source relaxation oscillator not starting

Vcc is 5 V , first op-amp LM358 provides 2.5 V ground for easiest possible relaxation oscillator build with MCP661 (2.5/5.5 V supply, 60 MHz operational range). I wanted to use it to measure values of ...
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1answer
28 views

Current mode operation of a Source Measurement Unit (SMU)

I'm studying semiconductor parameter analyzers. In particular, I have difficulties in fully understanding the circuit in the following slide, which represents an SMU operating in I-mode (i.e., it ...
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74 views

How can I measure the actual magnetic strength of my electromagnet to compare against my calculations?

I am interested in building small scale electromagnets and I wanted to measure their actual magnetic strengths to compare against my calculations. What are possible ways to measure the difference?
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30 views

What test points to do for a switching system measurements?

I am working on a high-performance switching system. I the old ones there was no big issue in just touching a gate with an oscilloscope probe, but this time I have high voltage and very short (5nsec) ...
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3answers
1k views

Why are oscilloscope input impedances so low?

My question is two-fold: Where does the input impedance come from? I'm wondering where the input impedance of your average multimeter or oscilloscope comes from? Is it just the input impedance to ...
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1answer
890 views

Calculating AC Input Power

I'm making an AC to DC power supply that connects to mains. There's an AC to DC converter, buck converter and a smoothing LDO that outputs a DC controlled with pots. I'm verifying the supply, and ...
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1answer
48 views

differential measurement vs ground

I am looking to measure an incoming V vs ground with an ADC (MCP3424 or equal). The Vin vs Gnd can be anywhere from -1.5V to +2.0VDC. I looked at using an op amp with level shift, when I came across ...
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2answers
54 views

Can CMRR of a data acquisition input be measured this way?

I want to check a data acquisition input or overall CMRR of a signal chain roughly by a simple method. Normally for a daq input CMRR is defined as: CMRR = 20×log10(Vin/Vout) where Vin is the common ...
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4answers
892 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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58 views

Interchangeable resistor

I have a PCB board where I am measuring the voltage drop across a resistor which is placed on the Vdd path of a small micro-controller. I would like to have a method for easily interchange the ...
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2answers
93 views

Why do long cables measured with a VNA show a “drop” in their attenuation curve?

I'm measuring the attenuation of several cables with a VNA (Keysight N5234A). When I measure the attenuation of long cables (10 m, 30 m, 40 m or 50 m) I realize that a "drop" appears at 500MHz (see ...
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1answer
60 views

Finding Wilson Current Mirror Output impedance

I am trying to confirm my output resistance calculations with my simulation. How can I measure the output resistance seen by Q4 in order to confirm my calculations? How I measured \$r_{o2}\$ (image ...
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74 views

Capacitor tolerance at high frequencies

I was measuring a 10pF 0603 +-5% (Johanson 251R14S100JV4S) using a network analyzer at 319.5MHz. The cap came in their high q/low ESR ceramic kit. It measured about 10.7pF. But after measuring a few ...
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1answer
30 views

How can I detect that a ZVD-style 'backpower protection circuit' is operating correctly?

I'm designing a circuit that needs a 'backpower protection circuit', similar to what the Raspberry Pi HATs use. This is meant to block voltage from the secondary board when the primary board is ...
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1answer
67 views

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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35 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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8 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
93 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
46 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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68 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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4answers
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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1answer
95 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
57 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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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
92 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
330 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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3answers
883 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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1answer
70 views

What instrument is used for measuring very low current / voltage? [closed]

I'm wondering whether galvanometer can be used or not ?
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1answer
26 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 ...