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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.

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857 views

Methods to measure inductance with high (1%) precision using standard equipment?

I am modeling the fine behavior of interacting oscillatory circuits. I have looked up a couple of methods for measuring inductance. I believe I am following the procedure faithfully, but the values I ...
5
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4answers
1k views

Why do LCR meter manufacturers give the details of measurement frequency to us?

When you want to purchase a DMM, more probably you don't see at what frequency the DMM you considered would work, but in the situation you're considering to purchase an LCR meter, manufacturers give ...
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0answers
25 views

Can I use a RF and/or Time-domain reflectometer to find 'wet contact'?

Friends of mine have a circuit where the RCD trips but only after prolonged rain. There are a number of garden and security lights on that circuit so I very much suspect there is a junction box where ...
0
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2answers
101 views

How isolation is achieved in isolated channel oscilloscopes?

I tried to search something about this but found only a small amount of information. What confuses me is that all isolation amplifiers, optocouplers etc. I could find usually work at much lower ...
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0answers
70 views

Darlington Transistor TIP142 same type but different values

I have a bunch of Darlington NPN Transistors TIP142 that are removed from two separate identical boards. The 1st one have the TO−218 CASE (left side of the image) and the 2nd the TO−247 CASE (right ...
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0answers
52 views

Measuring current in the case of bridge amplifier at several MHz

Is there a way (or some chip) to measure current at about 5 MHz when the bridge amplifier is used? The output is a sine with amplitude 15 V. I need to measure accurately both amplitude and phase (the ...
1
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1answer
59 views

How can I make my measurements of full-wave rectified AC using an A/D match a Fluke meter on its DC range?

I am trying to measure the DC voltage of a full-wave rectified 60Hz AC signal using an A/D and have it match what a Fluke meter reads on its DC scale. My current approach is to take as many (16 bit) ...
0
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1answer
27 views

Measuring a magnetic pulse using a coil, and circuit adjustments

I have the following circuit, I am using it to create a pulsed magnetic field, in the coil. I am trying to measure and verify the magnetic field in the coil. I am testing it with 40 V to drive the ...
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2answers
67 views

Non-intrusive measurement of current and voltage

Sorry if this question is too basic for this forum... I'm an interested amateur but far from a professional. I'd really appreciate information from someone more informed than myself. Hypothetical ...
1
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2answers
70 views

Measuring Inductance

I have been looking the number of methods to measure inductance of a coil if you don't have an LCR meter available, and I have had some difficulty. I designed and built a coil and I would like to ...
3
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3answers
95 views

Which components can be measured while soldered on a PCB board already?

I am assembling nonlinear oscillators on PCB boards for applied math research [Colpitts (100 kHz, 3 V_pp), FitzHugh-Nagumo (100 kHz, 15 V_pp)]. I am working with some other people that want to do ODE ...
1
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1answer
59 views

Measurements using spectrum analyzer

I need to measure the following characteristics of a frequency synthesizer using a spectrum analyzer: Frequency range: 2.286 GHz to 2.346 GHz Output power: -2.5 dBm to 2.5 dBm SSB phase noise: ...
1
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1answer
36 views

Voltage Measurement with ST Microcontroller

I want to measure DC voltages from 1mV to 10V. I will be using STM32L053C8T6 Discovery board. I want to use 3.3V reference voltage. I know that if you want to measure voltages bigger than reference ...
0
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1answer
41 views

Measuring Frequency Synthesizer specifications

I need to measure all the electrical specifications of the Frequency Synthesizer KSN-2346A+ from Mini Circuits that appears in this datasheet: https://www.minicircuits.com/pdfs/KSN-2346A+.pdf but the ...
0
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1answer
33 views

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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4answers
68 views

Oscilloscope coupling and effects on the measured signal

I have a basic understanding of the of coupling settings on an oscilloscope, but I need some help to understand what I am seeing on scope. I have a signal generator, with an arbitrary function set, a ...
0
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1answer
43 views

Problem in LC series resonance

I'm trying to experimentally verify my calculations on resonance on a simple series LC circuit. To prove resonance, I'm measuring the amplitude on the series resistor. When the amplitude is the ...
0
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2answers
51 views

Estimating torque of AC motor

Given voltage, measured current draw, and RPMs of an AC motor, and an estimated efficiency rating, is it possible to calculate the actual instantaneous output torque? Or is other information required? ...
3
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2answers
106 views

Oscilloscope: when to use coaxial instead of probes?

I understand the difference between passive and active probes, and between x1, x10, x100, ... I also understand that at high frequencies the capacitance of the oscilloscope has to be considered, so a ...
0
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1answer
46 views

RF measurement setup

I'm trying to take a simple measurement of ~2.4 GHz (WiFi land) with an RF spectrum analyzer (Tektronix RSA607A) but have so far been unsuccessful. On the RF In ...
0
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1answer
78 views

Measuring phase shift between current and voltage with microcontroller

I am trying to understand how this design is used to measure phase shift between current and voltage of an AC signal. From my understand there should be a PWM signal generated on the output. Resistors ...
0
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4answers
107 views

Multimeter, outlet and a Spark: the question of simple Voltage measurement

So I got a TekPower TP4000ZC MultiMeter. (Image source) It has COM port and two red ports: V-Ohm-etc. set at 600V Max and 500mA Max Fused 10A red fused port. Unlike other multimeters, there are no ...
2
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1answer
70 views

Zero-crossing in AC with DC offset signal

Introduction I have a project about measuring the voltage, current and power factor of an electrical system. I had designed a system that allows the microcontroller to measure the peak of an AC with ...
0
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1answer
36 views

R&S Spectrum Analyzer Voltage Measurement Error

I just got FPC1000 spectrum analyzer that goes from 5 kHz to 1 GHz. I didn't had any spectrum analyzer experiences before this one so everything is very new to me. Among few things that I don't ...
2
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1answer
84 views

How to measure a 100 ohm differential signal on a spectrum analyzer?

I have a pair of 1.5V PCML differential signals coming out of an Altera Cyclone V GX FPGA, terminated on the FPGA in 100 ohms with common mode voltage = 0.65V (also provided on the chip). I need to ...
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2answers
86 views

Measuring 0805 Capacitor values under 1nF

Other than investing in an expensive tweezer type meter for SMD components, what would be a good method for the layman to find the capacitance of an 0805 ceramic capacitor whose value is below 1nF? My ...
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0answers
55 views

MEMS Microphone noise floor power level & audio noise spikes measurement

I have a circuit with a MEMS microphone and would like to be able to measure the audio noise spike contents and check the noise floor power level in the audio circuit. My intention is to connect the ...
1
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0answers
93 views

Power consumption measurement on the bench

I've been using the Atmel Power Debugger to sort out power consumption issues on some µController based circuits... and have been pretty pleased. Unfortunately, it's limited to a maximum of 5.5 volts ...
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2answers
61 views

Modelling a temperature measurement system

The accuracy of a measurement system can be significantly reduced by loading effects in the system. A thermocouple is used together with an indicator to measure temperatures. The thermocouple has a ...
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0answers
32 views

Measuring resistance of switched load

I am in the process of designing a custom vaporizer. So the main coil with a resistance ranging from 0.2 Ω to 2 Ω is switched using a MOSFET shown in the circuit diagram below. ...
0
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0answers
32 views

Queries regarding multiple reflections

I have a measurement set-up as depicted in the figure below. The measurement settings are as following: Both Generator 1 were having carrier frequency 1 GHz and output power 0 dBm. No modulation as ...
0
votes
1answer
50 views

Is this current clamp meter measuring correct according to its specs?

A 24V DC power supply is supplying around 2.4A to a pure resistive load. The input voltage is 230Vrms. So I estimated the rms current drawn from the power network as: P/230 = (24*2.4)/230 = 250mA. ...
0
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1answer
52 views

How to determine operating frequency range of an unknown 2-port device (with VNA)? [closed]

I have a question on hand: "You have an unknown 2-port device, the black box. Find the operating frequency range. Show how to do this with a VNA. Think of the settings, why?" VNAs can have a very ...
1
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1answer
50 views

Difference between hybrid and resistive RF power splitters, and Frequency Response?

I am new into RF measurements, and have got a couple of questions regarding power splitters (hopefully common for all the models that exist in the market). What's the difference between resistive and ...
1
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1answer
221 views

Why do I measure 5V in this circuit when I should measure 3.3V?

I have an audio processor board that has a 5V -> 3.3V LDO. For some very strange reason, when I measure the voltage of the output of the LDO, I read 5 instead of 3.3V -- which by the way is a lethal ...
0
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1answer
70 views

What options are available for measuring grounded thermocouples?

I'm using 4 MAX31855 ICs to measure 4 K-type thermocouples and realized that 2 of my thermocouples have grounded junctions; I simultaneously also realized the MAX31855 is stated to not support ...
0
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1answer
66 views

Electronic detector to measure of distance? [closed]

I am not well known about electronic and it is my first question here, beforehand sorry for not qualified question. Let me try to explain what I am looking for: Is there chip or any another ...
-1
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1answer
69 views

Measuring change in magnitude of electric current due to change in conducting material characteristics

I posted this in the physics section. I now think this might be more appropriate section for these questions. I am looking for answers to the following: What is the order of magnitude of change in ...
-1
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2answers
68 views

optical path resonance distance measurement device, super useful for open source hardware if it would work [closed]

My head just tends to be full of open hardware and open manufacturing stuff, and one idea I have had for years and always wanted to try, but never could for want of access to an electronics lab, is a ...
0
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1answer
31 views

If I use a CAT 2 10x probe does my DSO need to be CAT 2?

I need to measure the harmonic distortion on a solar inverter (power output). I need to buy all the equipment from scratch and was wondering if my DSO needs to be CAT 2 rated if I use a CAT2 10x probe....
1
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1answer
47 views

Using a scope for an instrumentation and mains earth

When I make a measurement using a scope and observe transducer voltage output on the scope screen, I want to eliminate the noise as much as possible which is due to device and scope coupling or common ...
0
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1answer
83 views

What is the frequency shown on scope screen for this measurement?

I'm observing the noise of a voltage regulator output in AC coupling on a scope. Shown is a photo from the measurement: The FFT for the Vrms shows explicitly on the screen that there is around a 6....
1
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0answers
137 views

What's inside a reed switch that cannot be tested with a multimeter?

I'm shopping for reed contacts that are rated for 230V AC, because I don't want to use an always-on power supply just for a relay and a reed switch. This is surprisingly difficult, but I found this ...
0
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1answer
41 views

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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0answers
27 views

Effect of AC output impedance on a ratiometric measurement

I was planning to make a measurement with a ratiometric IC, so I will sense both the Vcc and the Vout from the chip as shown below. For cleaning up the noise and stability I also want to add a 5V ...
2
votes
1answer
66 views

How to translate high voltage 500 Vdc to 501 Vdc differential to low voltage 0 Vdc to 1 Vdc?

I have two high voltage nodes which I need to measure the differential voltage between. What I am thinking at the moment is the following... 1 - Use voltage dividers to probe the voltage at 1/1000, ...
3
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3answers
79 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. ...
2
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1answer
38 views

Selecting the equipment with the optimal 10 MHz reference

In a larger testbench I have 5 synchronized instruments (signal generators, ARBs, VSAs etc). I am trying to decide which instrument to take as "master". I rule out the older/cheaper parts (Tektronix ...
1
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1answer
63 views

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 ...
0
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1answer
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 ...