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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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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How to measure supply currents ranging from 1μA to 10mA?
I’m building a battery powered data logger with a microcontroller and several sensors. I’d like to measure the supply current of individual parts with idle currents in the μA range and peak currents ...
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RLC equivalent model and Impedance Smith Chart
I have done some impedance measurements on an unknown 1 port device. I have measured its impedance at different frequencies (from 10 MHz to 600 MHz) and I have seen it on the normalized (on 50 Ohm) ...
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Measuring Vackar Oscillator Output Amplitude and High Frequency Effects
This is somewhat related to my previous question regarding why I wasn't seeing a clamp biasing effect with my JFET Vackar oscillator. I think I figured it out and I'm wondering if you guys agree. ...
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Measurement of transformer with a vector network analyser (VNA)
I have a planar air core (no ferrite) transformer in a PCB. I need to characterize the transfer function of this transformer from DC to 500 MHz using a vector network analyser (VNA).
My first ...
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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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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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Why are null measuring methods considered to be very precise?
I heard a professor saying "it's a null method, so it is very precise".
He was talking about the force balance pressure measuring method.
I think in this category of methods one can include ...
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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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How to measure the consolidated power of two electric motors, operating on separate axles of a 4x4 vehicle?
There may be two scenarios:
1- motors are identical
2- motors are not identical
I wish to know about the consolidated power for:
1- maximum power
2- continuous power.
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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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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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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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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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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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Series/parallel combination of resistance/capacitance in an RC circuit (wrt LCR meter readings)
I have this equivalent circuit I am working on. I have to find out individual values of all components in it. I can measure resistance, capacitance and impedance of the whole circuit. I am not sure ...
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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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Is it possible to save data from a network analyzer?
Im using N9917A Network Analyzer for measuring s-parameter values. I have connected the VNA to PC via Ethernet cable, where I can view the resulting plots of s-parameter values. If i get 15 plots of s-...
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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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Measuring inductance and ESR of a motor using LCR meter
I am building a circuit, where a MCU will drive an unipolar stepper motor through MOSFETs and constant current source (not included in the schematic).
simulate this circuit – Schematic created ...
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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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Tektronix TDS3000 series max trigger rate
So I am making a testing stand for some equipment and I am using an old TDS3034C Tektronix scope for most of my measuring purposes. I've connected it to the computer via Ethernet and using PyVisa to ...
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Measuring battery resistance
I am trying to measure the resistance of a AA alkaline battery. The circuit I am using is shown in a photo below. I have also attached the values I obtained.
Somehow, the values I am getting ...
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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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LTC1966 Sallen-Key post-filtering application question
Just a quick question about an application circuit in the LTC1966 datasheet.
Figure 13 on page 18 shows a third order (when considering output resistance of the LTC1966) Sallen-Key filter, with a ...
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How can I measure -170 dB GPS signal with a spectrum analyzer?
I'm looking for a way to measure noise signals (probably MCU harmonics) that affect the performance of my GPS receiver (Ubox sam-m8q-0-10.) Can anyone point me to the right direction?
I own a spectrum ...
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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 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 ...
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Energy meter neutral current measurement
I was reviewing an energy meter specification and I came across neutral current measurement.
What is the importance of neutral current measurement in an energy meter for three phase power supply?
I ...
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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 ...
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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 ...
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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 ...
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Source impedance influence on DC/DC converter input impedance measurement
simulate this circuit – Schematic created using CircuitLab
I have been tasked to verify the input impedance of a medium powered DC/DC converter (<1kW), and no experienced colleagues to ...
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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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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)....
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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 ...
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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, ...
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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....
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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Measure weights with arduino
I want to measure weights with arduino. After the measurements, i want to analyze the weight data of the measured objects.Precision is not very important, but it should be work in the range of 10 to ...
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