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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What are the disadvantages of crocodile (alligator) probes? [closed]
When measuring with an oscilloscope, I use an original high frequency oscilloscope probe and a double side crocodile (alligator) clip and the results are usually very close.
Note: it is called ...
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How to measure Lithium-ion battery SoC?
I have a 48 V 12 Ah Lithium-ion battery pack.
I am struggling in finding a way to measure its State of Charge.
It will be charged through a 13S JBD BMS.
I need to spit out information from the battery ...
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How to Read Unipolar Square Waves on TRMS Multimeter
I'm trying to switch from reading my high-voltage unipolar square wave signal from a benchtop oscilloscope to a handheld multimeter, but I don't understand why my multimeter is giving the voltages it'...
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Using 50 Ω coax cable instead of passive probe
Preface, why am I asking this question?
Instead of using a passive probe with a ground clip, I want a more "permanent" and reliable connection for my measurements. Note: I'm not talking ...
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How to measure multiple resistances with Arduino Uno, without one measurement influencing the other?
I'm working on a project where I aim to measure resistances using an Arduino Uno. I started with two separate voltage dividers, each using a 1 MOhm reference resistor, connected to a common Arduino ...
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What is the real resolution of my voltage measurement when I use only some of the range of of the ADCchannel
I have a 16 bit ADC, I use the +/1 V range, differential channel. If I used the full range of the ADC to provide full resolution (I am aware non-linearity and noise may affect this) this calculates as:...
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My isolation transformer has its protective earth connected to the output neutral. How should I rewire it for my home lab for "DUT probing"?
I have a rather sturdy isolation transformer in my home lab and I just realized that the primary side earth is not only connected to the output side earth but also to the output side neutral. I don't ...
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What does an accuracy of 0.1% + 20 mV mean in a power analyzer's data sheet?
I need to know the measurement accuracy of Keysight N6705C power analyzer. I came across this document (N6700 Modular Power System Family.pdf) that states the error in terms of a percentage plus a ...
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Understanding Voltage Read in Voltage Divider for NXP S32K118 Microcontroller ADC
I am having a bit of a hard time understanding the voltage read in the voltage divider that is being an input for an ADC to an NXP microcontroller, S32K118. Below is the schematic of the circuit.
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Determining Suitable TRMS Voltmeter Specs for Modulated Signal Measurement
I'm seeking advice on selecting a TRMS (True RMS) voltmeter suitable for measuring the voltage across a resistor with a modulated signal. Here's the scenario:
I need to measure the TRMS voltage across ...
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Induction motors torque measurement
I am to calculate the running efficiency of a 3-Ph squirrel cage induction motor. I have the rated data for the motor. I have the load speed of the motor but I need output torque to calculate the ...
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Pulse width modulation using ML4800CP
I am working on a SMPS (450 V output). It use an ML4800CP IC to control and manage 450 V DC.
How can I measure the PWM signal using an oscilloscope? I attached it, and it worked well for the PFC ...
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Measuring nA leakage current
I'm trying to measure some leakage currents of both a diode (expected around 5 nA) and a MOSFET (20 nA).
My issue is my meter's measurement accuracy is only around 10 uA, and I need an accurate ...
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Why might my circuit's measured voltage drop when I add more load to it?
I have one of these power supplies:
I also have an MCR-4V data logger:
If I connect wires directly from the power supply to the data logger (red to red, black to black), then the voltage output on ...
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Mass paralled resistors for better tolerance [duplicate]
I hope this doesn't get people's eye rolling as a very rudimentary question...
Here goes. I need a very, very precise resistor divider, say a 1/11 ratio. It doesn't really matter the ratio chosen. ...
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Are LCR meters sensitive enough to measure PCB trace impedance? [closed]
How long is a piece of string?
I’m working on an application currently where trace impedance appears to make all the difference on performance as observed on a few unguided experimental revisions of ...
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How "Zero" is this supposedly Zero-TCR resistor? And how much better is it than this other one?
I found a resistor at Digikey, and the TCR was quoted as being 0.0ppm/°C, and I had to check the datasheet just to refute my suspicion that it was a data entry error, and it looks real, but just how ...
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Can I measure the internal termination resistance of a MIPI receiver?
This question is further to: How accurate are internal terminators on chips with high speed differential inputs?.
I would like to measure the actual termination resistance inside one of these chips (...
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Measure capacitance with Arduino and AD7746
I want to measure capacitance with an Arduino and an AD7746 capacitive sensor.
I already used ChatGPT and some examples, but the sensor measures just 0 pF. When I measure with an LCR meter, the ...
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Resistance measurement with DMMs
I had one doubt regarding resistance measurement from multimeters. I cannot show the schematic because it is confidential but I have added a circuit diagram. It refers to a gate driver circuit.
I am ...
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Comparison of two methods used to calculate capacitance
I need to compare two potential methods used to calculate capacitance, but I can't find the names for them to do some research.
The first method: Placing a capacitor in a circuit with an 800 Hz ...
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Measuring impedance on VNA
Question:
I would like to measure the impedance and phase of an electric piezo tranducer with a resonant frequency of approximately 1MHz - a graph of impedance in Ohms as a function of frequency.
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Measure transformer real power
I’m new at making transformers myself, and the ones that I designed had the correct output voltage, and when they were connected to batteries (previously rectified), they give me a an approximate of ...
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How to determine C-rate for DIY batteries?
I am investigating some DIY battery chemistries and construction, as such they do not have a known C-rate. How would one measure this? How is it determined for commercial batteries? There seems to ...
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Are there any tricks for measuring high voltages (~1000 V) efficiently?
The simple way to measure voltages above VDD is to use a resistor divider. However, once you get into the 100s of volts these dissipate significant power.
For example, one of my current designs ...
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Uncertainty for measuring a resistor
I am trying to calculate the uncertainty of a measure on a resistor. The expected value of the resistor is 45 mΩ. For measuring the resistor I used the two following instruments:
SM500-CP-90
Agilent ...
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Capacitor test mode in ICT
My ICT machine has two capacitor measurement modes on the PCB:
Mode 1: Use DC source test method (Figure 1)
Mode 2: Use AC source test method (Figure 2)
Could anyone please help me with the ...
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Which is the best method to measure AC voltage?
I am trying to make a UPS circuit. I need to have a high speed measurement for the input AC voltage (220 Vrms) (in order to know whether to turn on/off the inverter). I had tried using this circuit:
...
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What could be the possible reason for waveform distortion while connecting differential probe GND with single ended probe GND?
I am measuring following waveforms using a DSO:
Case 1:
Waveform 1 wrt GND using differtial probe.
Waveform 2 wrt GND using single ended probe.
Result 1: Waveform 1 distorted.
Case 2:
Waveform 1 wrt ...
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How can I find the diameter of a wire if I have the length and resistance? I cannot use measuring tool because wire is thinner than 0.1 mm
As the title suggests; I am trying to calculate the diameter of a wire given its length and resistance.
Specifications:
Length: 30.4 cm
Resistance: 17 Ω
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Do digital multimeters work the same in vacuum?
We want to use a RS14 Handheld Digital Multimeter inside a glovebox and therefore we submit it to vacuum (0.1 bar) to come in and out of it, and to inert N2 atmosphere once it is inside the box.
Does ...
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Matching network for two-port with internally matched inputs/outputs
Background
I had a lab in school where we were given an LNA with inputs/outputs matched to 50Ω, that will be connected to a 50Ω system:
The task was to design the input and output matching networks:
...
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How can I describe the loading effect of an ohmmeter?
How can I describe the loading effect in an ohmmeter? I've been given an assignment with this question, and I tried to look it up on the internet but could find no other material apart from loading ...
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Tension load cell options
I'm designing something similar to an electronic hanging scale (think a heavy object on the bottom, with a scale attached immediately above it). I am not that familiar with what the most typical way ...
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Test lab noise floor variance and emission limits
I have recently taken part of noise floor measurements for emission tests from two separate EMC labs, both well known and international companies. The thing that shocked me is the dramatic difference ...
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Contactless measurement of internal time base
I'm currently trying to measure the internal time base of stopwatch (both mechanical and digital) to ascertain the expected accuracy of the device. I have looked through many articles related to the ...
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How do I calculate the minimum deflection I can sense with a strain gauge, like the BF350-3AA?
I have a strain gauge (the BF350-3AA), and I will be connecting it to an HX711-based amplifier sensor.
From its low-quality datasheet, I've pulled out the following figures:
Nominal Resistance: 350 ...
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How can I correlate a RSSI value to a distance measurement more efficiently?
I want to develop a trilateration algorithm using 3 fixed advertising beacons in different parts of a room and a mobile receiver which continuously gets the RSSI values of the 3 fixed beacons and ...
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HLW8032 energy meter circuit showing power usage at no load
I am designing an AC energy metering circuit. The circuit has to measure voltage, current, power, power factor and energy used for two channels (from the same source). The HLW8032 transmits 24 bytes ...
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Can I use 12 V and -12 V together?
I am sorry if this question is pretty easy but I am a beginner.
I have a PC PSU that provides two lines:
12 V 11A
-12 V 1.5A
If I used them together will I get 24V, and how many amps can they provide?...
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Measuring flyback SMPS feedback loop response
I'm trying to measure the feedback loop on a isolated flyback SMPS. My goal is to determine the phase margin and 0 dB cross-over frequency.
The most common circuit I have seen is the one recommended ...
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AC leakage issue with high impedance measurement setup
I am having an AC leakage current problem with my measurement setup that I typically use for lock-in measurements.
I employ a 100 M\$\Omega\$ resistor as a voltage-current converter, and in series, a ...
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Measure power & energy usage in tapped line
Here is the schematic of the circuit in question:
The horizontal lines are from the AC mains. Ammeters and wattmeters are connected at any 2 points in the main lines. I am trying to detect if the ...
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Measurement of relay characteristics so can detect before failure
I am working with a very large safety system which was designed around 30 years ago. It has a system of relays interlocked together in a logic configuration so that it will failsafe if any relay ...
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Debugging PLL STW81200TR not locking
I need a bit of debugging help with SWT81200 PLL that I am using on my custom designed PCB. I am able to configure registers through SPI communication, but the problem is that I am not able to achieve ...
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Criteria to see if a battery was over-discharged in the case of Li-ion cells and NiMH batteries
Consider a Li-ion pouch battery from an RC model. Is there any reliable way to determine by measurement if the battery was in a over-discharged state in the past. (In particular I am looking for ...
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Connecting LVDS to oscilloscope using ferrite bead to isolate GND/SHIELD
I want to measure LVDS signals with a scope.
Will my solution work? (Shown at bottom.)
I know of other ways of doing this, but I am hoping this way is cleaner and easier.
Specs:
Frequency:~100MHz
...
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S11108 Circuit Design Logic
This is my first post and also my first dip into electrical engineering, and I wanted to ask if you have any suggestions on the circuit I have designed. As a background, I'm a Computer Science student,...
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Using a DAC to measure system gain
I am using a Wheatstone load gauge through an AD8295 op-amp to a SAMD21 uC ADC. The op-amp uses a resistor to set gain. An analog switch is used to change gain. Since the resistors are not exact (G = ...
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How to eliminate internal circuit current consumption from the measurement in bi-directional current measurement circuit?
I am comparatively new in this domain. I am trying to design a bi-directional current measurement circuit. This is a 5V to 9V DC system. I have two USB C female ports at both ends. Which means I can ...
