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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.

704 questions
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### 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 ...
126 views

### Did I ruin my multimeter with a current measurement?

I am trying to do a current measurement. Probably I accidentally put it it parallel instead of in series. What I tried before/after that (cannot remember exactly putting it parallel but might have ...
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### Impedance magnitude and phase error - Mathematical formula

Today I read a paper on which there are the terms magnitude error and phase error relative to a comparison between measurements performed with a biosensor and with a benchtop electrochemical impedance ...
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### Measure input capacitance of I/O pin

I'm looking for a simple laboratory procedure (and required equipment) to measure the input capacitance of each IC I/O pin. Thanks in advance.
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### Negative Voltage Reference for Bipolar ADC

I am considering using ADS1258 - a bipolar ADC. It needs an external reference across REFP(+) and REFN(-). How do I generate precise -2.5V assuming I have +12V and -12V analog voltage rails? I can ...
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### No output reading from Op Amp on Oscilloscope

So I have an inverting op amp (gain = -1) wired up, and it works with a DC signal. I checked the DC signal by measuring the input and output voltages with a multimeter which were 5V and -5V, ...
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### Converting Uncertainty in dB to Relative Standard Uncertainty

Data sheets often give uncertainty in dB. If uncertainty is specified as a percent, I believe that means it is a relative uncertainty. Assuming the coverage factor is one, the relative standard ...
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### How to measure tilt on a dynamic device?

I'm trying to instrument a vehicle component. I want to measure a component's angle during a drive cycle. The component has a single degree of freedom, it has a fixed axis. I'm trying to figure out ...
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### RF signal generator, spectrum analyzer measurement questions

I want to test the attenuation characteristics of an RF filter I’ve built into a project, but do not have any experience using RF signal generators or spectrum analyzers. In all of the videos I have ...
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### Building a DIY Oscillocope

I have decided that I would like to design a DIY DSO Oscilloscope, the idea has been in my mind for a while, I just haven't had the time to look into it, I am surprised as there doesn't seem to be ...
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### What is the principal of Inductive Conductivity sensor?

What is the principal of Inductive Conductivity sensor which uses two coupled coils to estimate conductivity? Image Source I understand that the eddy current losses changes with the conductivity, ...
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### What is and how to measure the tuning port capacitance of a VCO

I was asked to check all the specifications of this Voltage Controlled Oscillator. I might have an idea of how to measure all the parameters except for one, the Tunning Port Capacitance. I think my ...
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### What is the use of making measurements using both forward and reverse currents? (Kelvin bridge)

For measuring low resistances using the Kelvin double bridge arrangement it was mentioned in our electrical measurement lab class that we should use both a forward current and a reverse current (i.e. ...
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### How do current probes load a circuit?

It's usual to talk about loading a circuit when measuring voltage, with a voltmeter or with a voltage probe and an oscilloscope. It can be seen as putting an impedance in parallel to the element whose ...
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### How do I measure very low frequency noise?

I'd like to measure low-level noise in the 1 Hz to 100 kHz range, for example at the output of a LDO. For higher frequencies a spectrum analyzer would do the job, but most only go down to the MHz ...
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### Is it not recommendable to use a spectrum analyzer in its limit frequencies?

Suppose we have a spectrum analyzer whose range of frequencies goes from $x \ \mathrm{Hz}$ to $y \ \mathrm{Hz}$. Is there any problem that could arise from measuring signals that are near those ...
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### Can any meter be PT connected?

I have an EE background, but am new to metering hardware. Looking at metering equipment for high voltage measurements (up to 6.6 kV), it seems most only go up to 480 V, even when classified as ...
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### Measuring temperature of fluids inside a glass tube

Suppose I have some experiment with some fluid (e.g. water or milk) flowing through (or just residing in) a cylindrical tube made of glass. What would be a good way to "non invasively" measure the ...
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### 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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### 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 ...
91 views

### What to look for in an isolation transformer?

What do you want from an (isolation) transformer besides it having the minimum voltage/current/power(/frequency?) specs that the to be isolated device needs? Does it matter whether the transformer is ...
135 views

### How do you know that an oscilloscope is displaying the actual waveform?

As oscilloscopes get faster and faster, when designing a new scope how do you know that what it's displaying is the same as the actual waveform? For the fastest scopes, you don't have something ...
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### Period Measurement

I am reading a book about the measurement in communications. There are a lot of information about how to measure frequency and period of signals. OK, i have understood that we should measure the ...
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### Dictionary: is PWM precision the same of PWM resolution?

I have an issue in identifying the meaning of PWM precision. I've always talked about PWM resolution, and to me seems to be 1/2^(n-1). Is the precision of the PWM just prequency precision? Or is the ...
447 views

### Why is this the maximum dynamic range in a spectrum analyzer?

In Keysight's popular AN 150 there is a plot of noise and harmonics amplitudes versus the level of the input signal at the mixer (page 57). It's stated there that the maximum n-th dynamic range is ...
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### Output impedance of a 4mA to 20mA current loop

I have the most basic of basicness circuit. The implementation is a XTR115UA IC with a 40µA - 200µA input (based on sensor voltage) which is amplified to the desired 4mA to 20mA current in the current ...
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### Detecting velocity in a specific threshold [closed]

I have three velocity sensors that are axis in 3D. I would like to know the best method to do basic ON/OFF trigger.. I'm thinking of a hystersis control, is there a method that can detect if the ...
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### How to measure remaining lithium battery charge accurately (destructively)?

I want to measure the remaining charge in batteries and my requirements may be somewhat unusual. I do not need to preserve the charge left in the battery and it doesn't have to be quick. All I want is ...
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### Techniques for probing circuits that would normaly be covered by a heatsink

I have a circuit board I have to probe and measure to first debug and then later on verify performance. The circuit board contains a power amplifier that requires a heatsink in order to keep the ...
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### Measurement of total AC resistance (including radiation resistance) of a coil using LCR meter

If we measure AC resistance of a coil using an LCR meter (or impedance analyser), does it include both ohmic resistance and radiation resistance? I understand that the radiation resistance is ...
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### 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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### Is the carbon-zinc battery that I am characterising overloaded? Using HPPC

I am trying to characterise a 9 V battery using a pulsed load measurement. The battery is a 9 V zinc-carbon eveready super heavy duty. The load is a controllable constant current source. When I ...
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### Can I use a scope probe to connect a signal generator to a generic circuit?

It's an exam question stated as in the title. I don't know how to analize the problem. As long as it's a BNC to BNC coaxial cable anything goes I think, but I don't know for attenuating probe or ...
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### Question about a trigger input of a modern ARB/VSG (Vector Signal Generator)

Given a common setup: The green box is a PCB mainly consisting of a data acquisition device (ADC+RF frontend) which is controlled by a Spartan-6 FPGA. The ADC & FPGA use a clock from a Tektronix ...
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### How does capacitive coupling work for measurements

The context is the measurement of engine speed on a vintage car that uses a classic Kettering ignition system. Essentially, a voltage pulse of tenths of kV is generated on a high tension (HT) lead. ...
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### High Voltage Measurement

I went for an interview for scientist position in BARC India. They asked this problem How will you measure a high voltage like 765kV AC ? I replied that we can step down using potential transformer ...
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### Battery monitor on ADG507 and AD7705

I'm developing a battery monitoring circuit. There is a problem. I launch a survey of all ports ADG507. For the test, I connect only two power supplies instead of the first and second batteries. The ...
395 views

### Measuring differential signal with single ended probe

I have a differential signal(a +/- signal) to measure. Can I use a single ended probe to measure it and then just multiply whatever I read by 2 to get the actual amplitude?
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### Determine to Assume Outer Diameter of Cable for Choosing Cable Gland

Is there any method to determine the cable outer diameter just only known from the pin connector which is M23 Connector 17 Pins? I need the method for choosing cable gland size. Thank You
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### 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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### How does temperature compensation work for strain gauge in wheatstone bridge

Wheatstone bridge is used for temperature compensation for strain gauges If 2 strain gauges are connected like this figure. Due to temperature variation; the resistance Rg will change in the same way....
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### How does 3-wire RTD or resistance measurement works in bridge of wheatstone?

I cannot understand how 3-wire measurement will improve the resistance measurement. They say that IF lead resistance $R_L$ is the same, it will compensate. How can this happen? If bridge is ...
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### Is the gain from IIP3 curves wrong?

Suppose I have an unknown system and I would like to know its linearity. I am confused by the proper measurement of the IIP3. The gain is defined as "total output power" divided by "total input power"...
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### Current to voltage converter and voltage follower

I am designing a current to voltage converter for my sensing device. followed by a voltage follower or a buffer. by varying vcc, so that i can achieve sensitivity of my circuit. do i need to have same ...
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### Getting Agilent USB GBIP Adapter to work with NI-Visa or R&S GBIP over USB with Agilent Visa

This Visa/IVI jungle is pretty much a desaster. Not enough that each package contains GBs or data, they also cause problems when installed in parallel (one example: https://www.mathworks.com/support/...
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### Measuring resistance

I would like to measure the resistance of a resistor in the most basic way by running a current through it and measuring current and voltage. I understand that I have basically two options to place ...
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### 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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### Why IR remote waveform is a saw-tooth or am I measuring it wrong

The measurement circuit is as follows: simulate this circuit – Schematic created using CircuitLab The waveform looks like this in my measurement: Is this because I'm measuring it wrong and ...