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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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 ...
Claudiu's user avatar
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6 votes
4 answers
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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. ...
Tempus Nomen's user avatar
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How to wire a circuit to measure the duration for which current flowed through a wire? [closed]

There are no direct instruments to measure duration of current flow. I've to design a circuit which can calculate ON duration, Operation duration and OFF duration of a circuit.
Domino's user avatar
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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 ...
Alex Turner's user avatar
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3 answers
640 views

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 ...
MicroservicesOnDDD's user avatar
2 votes
2 answers
122 views

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 (...
Rocketmagnet's user avatar
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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 ...
KangHyuk Lee's user avatar
1 vote
1 answer
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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 ...
Andr7's user avatar
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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 ...
Emmannuelle_Legolas's user avatar
1 vote
1 answer
80 views

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. ...
piotr's user avatar
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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 ...
samuel mattio's user avatar
1 vote
1 answer
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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 ...
MadMaxx's user avatar
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7 votes
6 answers
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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 ...
Drew's user avatar
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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 ...
Jess's user avatar
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1 answer
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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 ...
Hoài Nam Nguyễn's user avatar
2 votes
2 answers
368 views

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: ...
Hazardous Voltage's user avatar
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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 ...
Divya K.S's user avatar
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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
Monesh Rathod's user avatar
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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 ...
psansoldo's user avatar
1 vote
0 answers
46 views

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: ...
Hugo Lundin's user avatar
1 vote
2 answers
187 views

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 ...
Prabhat Sharma's user avatar
2 votes
2 answers
55 views

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 ...
honkskillet's user avatar
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1 answer
77 views

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 ...
NoobPointerException's user avatar
1 vote
0 answers
64 views

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 ...
User988812119's user avatar
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1 answer
91 views

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 ...
HumpbackWhale194's user avatar
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0 answers
43 views

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 ...
Theodor's user avatar
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1 vote
0 answers
208 views

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 ...
k.h's user avatar
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5 votes
1 answer
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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?...
Mohamed Essam's user avatar
0 votes
1 answer
77 views

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 ...
jpa's user avatar
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1 vote
2 answers
134 views

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 ...
183iuU's user avatar
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1 vote
2 answers
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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 ...
Puspam's user avatar
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7 votes
6 answers
821 views

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 ...
REPuzzle's user avatar
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0 votes
2 answers
17 views

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 ...
Vasja Pira's user avatar
2 votes
1 answer
41 views

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 ...
martin's user avatar
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0 votes
0 answers
72 views

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 ...
Tony's user avatar
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2 votes
0 answers
91 views

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,...
Alex Riddell's user avatar
2 votes
2 answers
82 views

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 = ...
Magno Grail's user avatar
0 votes
0 answers
32 views

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 ...
Sakhawat Fahim's user avatar
0 votes
2 answers
52 views

Can I measure pinholes in a dielectric layer using LCR meter?

I have a thin dielectric film (~1 um) and I want to measure the quality of the film in terms of not allowing leakage current through pinholes. Can I use an LCR meter for this purpose? If yes, how? If ...
SNIreaPER's user avatar
2 votes
2 answers
67 views

How do you characterize the noise in a fluid velocity measurement device?

I have designed and built a measurement device that detects the velocity of a fluid flow (a constant-temperature anemometer). I wanted to experimentally characterize the noise performance of the ...
everettAdams's user avatar
0 votes
1 answer
66 views

Optical distance measurement idea [closed]

Ok, so I posted this using my phone some time ago, more than a year ago. However let's just take it from the top, integrating the criticisms that I remember. I am a cnc machinist by trade and we ...
user7311634's user avatar
0 votes
1 answer
41 views

Questions about connecting ADS1115 for voltage measurement

Purpose: to measure the voltage on the DC bus (about 600VDC). ADS1115 Datasheet I looked at the use cases and saw two connection options (in the first case, we use two inputs, in the second, only one)....
Delta's user avatar
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0 votes
1 answer
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Sigma-delta modulator (ADC), can it be used without sinc3 filter?

Purpose: isolated measurement of DC voltage (about 600V). For these purposes, I found two options: ADS1115 (I2C ADC) + I2C digital isolator CA-IS1204 Isolated Sigma-Delta modulator I am considering ...
Delta's user avatar
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3 votes
1 answer
191 views

74LS283 4-Bit Adder doesn't work as I expected. It sets some inputs to high voltage

I bought a few cheap 74LS283 chips. They don't work as I expected. For some reason it sets the A1 pin to high voltage (5V) at all times. Considering the A1 and B1 pins are supposed to be input pins, ...
Altrey's user avatar
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0 votes
0 answers
55 views

Generating Double pulse using Tektronics Function generator AFG31000

I have Tektronics AFG 31000 function genertor with built in double pulse test app. I want to generate two pulses for my double pulse test but this so simple task is becoming a mountain to climb for me....
Alison's user avatar
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12 votes
6 answers
5k views

Why can't capacitors on PCBs be measured with a multimeter?

While looking at this article, it mentioned that one cannot test the capacitance of a capacitor while it is on a PCB. The explanation given is: The reason is, that when a capacitor is inside the ...
HFOrangefish's user avatar
0 votes
1 answer
56 views

Current measurement in every 20ms

I want to measure the current in every 20 ms and record the measurement. I was using the Fluke DMM and in that I am not able to measure something less than 125 ms. Could someone suggest any methods ...
Teena's user avatar
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0 answers
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A question about scope's channel affecting other

I have the Digilent's USB scope and when I couple different signals to Ch1 And CH2, the channels affect each other. I didn't observe this with another USB scope. If both are coupled I get the ...
user1245's user avatar
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5 votes
3 answers
458 views

measuring frequency with opto-isolator

I have a circuit where 220VAC mains is stepped down by transformer to 48V and through an 5k1 resistor I'm activating optocoupler that drives a LED through a resistor on the other side. I am measuring ...
greengold's user avatar
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0 votes
0 answers
69 views

Is a semi anechoic chamber with absorbers on the floor a fully anechoic chamber?

I have a question about radiation measurements according to EN 300 328. According to the ETSI EN 300 328 V2.2.2 (2019-07) standard, measurements can be performed at one of the following three test ...
Not A Hobbit's user avatar

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