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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How to trigger oscilloscope on a PAM-5 signal

How do you configure the trigger of a sampling oscilloscope to trigger on a PAM-5 (Gigabit Ethernet) signal so that it produces an eye diagram? Edge triggering doesn't seem to work very well.
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2answers
78 views

How to determine the power needed for a device without knowing info about the device? [on hold]

I recently started a couple projects where I take apart old appliances and re-purpose the old parts. The problem I ran into was that I don't know how much power I need for some of the parts to run. ...
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1answer
46 views

Voltage divider with ADC

simulate this circuit – Schematic created using CircuitLab I am a newbie and this may not be a tough one. I am using Arduino UNO and trying to find the unknown resistance with the above ...
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1answer
39 views

Resistance measurement using high side current sense amplifier

I want to measure very small resistances (0.5 to 1 Ohm) using a high side current sense amplifier. The device I have in mind is MAX9611. The typical application circuit from datasheet is like: My ...
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2answers
72 views

System Grounding and Mixed Supply Grounding

I'm attempting to prototype this curve tracer (http://www.vintage-radio.info/download.php?id=224) mainly following the original design, but altering it to suit my own requirements (serial connection ...
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1answer
332 views

RC oscillator ageing

I know that a crystal oscillator has a particular ageing curve, that shall be taken into account when designing a long-term application. But what about the RC internal to the MCUs? I did not find ...
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1answer
75 views

How to detect a (very) small change in the position of a needle? [closed]

I am very sorry if my question is too basic (or odd), but I do not know anything about electrical engineering. I would like to mimic the motion-sensing filiform hairs in spiders and insects: The ...
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2answers
104 views

Which Multimeter is correct?

I have two Multimeteres that I'm using to measure resistance of a 10 Ohm resistor. Now, when i measure with the first one it's showing 10.2 Ohms while the other is constantly changing values from 9.9 ...
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1answer
46 views

Should I connect ground for differential measurement with oscilliscope?

Suppose I need to view voltage between two arbitrary points of a circuit with an oscilloscope. For that I can use two probes and A-B math, but should I connect the ground lead to the circuit? How to ...
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1answer
73 views

Measurement of marine propeller pitch

I have a small project that I'm trying to figure the cheapest and most reliable method for. I. Wanting to measure various points along an outboard motor propeller to gauge the exact pitch to be able ...
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3answers
84 views

Increasing sensitivity for voltage measurement

I am trying to differentiate between two kind of marbles. I am using the marbles as a second resistor in a voltage divider and measuring the voltage drop on it. Theoretically there must be a ...
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1answer
35 views

12v (ish) measured by a 0-3.3v input pin [duplicate]

firstly apologies I'm a newbie at practical electronics! I have a sensitive little thing which can measure 0-3.3v DC in steps of 0-1023. I'd like to use it to measure the voltage on a "12v" vehicle ...
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2answers
84 views

Principles for premature failure analysis of PCB tracks and vias

I have just given a task to implement a setup to detect whether or not a track or via on a PCB is going to fail in any time in the future. The PCBs are supposed to be used in harsh environment e.g. ...
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0answers
38 views

How to measure 3phase RMS currents in PSCAD

I would like to measure 3 phase rms current as well as voltage of a load, In PSCAD 3ph rms voltage measuring block is available but there is no such block for current.
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1answer
70 views

op amp oscillation problem during chip measurement

I had an oscillation problem when testing my fabricated chip. As shown in these figures, the transient waveforms of the op amp outputs got severe oscillations. Ch1 and Ch2 are the two output nodes and ...
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2answers
87 views

Measuring Power Consumption of a Mixed-Voltage Device

TL;DR How can I measure the power consumption of a system that uses power supplies with multiple voltage outputs? Background I need to perform some power consumption tests on a desktop computer. I ...
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2answers
55 views

How to check what is the percentage of charge in my lead acid battery?

http://www.allbatteries.co.uk/media/pdf/AMP92108_FR.pdf I want to know how much percentage of the battery charge is left without buying any fancy equipment to measure it.
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0answers
33 views

Trouble in tracking measurement offset

There is a 24V power supply unit which powers 8 transducers such as temperature, air pressure ect. All transducers are powered from this same power supply. The transducers' outputs are hooked up to ...
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1answer
40 views

How to evaluate equivalent 'samples per second' from Time base value?

The following is from Tek DSO manual about the Time base and sample rates. When i turn the knob further, i am able to read values like M 100ms or M 250ms. What woud these evaluate to in terms of ...
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1answer
129 views

How do i measure -50 v to 50 v using At-mega micro-controller

I am working on a project where i require to measure -50 v to 50 v using At-mega micro controller(10 Bit ADC). I have tried voltage divider circuit for the positive side of the voltage range which ...
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1answer
55 views

Measuring old capacitors - what could cause large deviations?

I'm measuring an assortment of old electrolytic capacitors ('elcos') to see if they are still okay, using my digital multimeter (a simple Duro AL-205). I noticed that most of the values are higher ...
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1answer
77 views

Is it practical to measure an unknown capacitance by measuring its impedance?

I've recently seen some fourth year engineering projects at my school (University of Waterloo) and one that I found interesting was this novel pressure sensor that uses nano silver separated by a ...
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2answers
56 views

High-current capable, high precision sine wave

I'm actually asking 2 questions - one about sine wave generation and another about high rate / precision voltage measurement. I'm working on a project where we have to generate a sine wave on top of ...
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1answer
64 views

How this device “Electronic Anti-lost-Anti-theft-Flashlight” measure distance?

Sorry i don't speak english but ill try. We want to design a system of a receiver and transmitter in RF, that it "beeps" when it is a certain distance one of each other. I found this: ...
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0answers
31 views

How to measure abdominal girth (measurement of the distance around the abdomen) using sensors?

I need to come up with a way of measuring the abdominal girth using some sensors with an accuracy of at least 0.5cm. It will be used to monitor patients in a hospital. It has to be totally automatic ( ...
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1answer
103 views

why have the same V before and after resistor?

I'm starting in electronics, and some measurements are surprising to me... Why i have the same V before and after a resistor? I've taken two photos to illustrate it, any advice will be very ...
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131 views

How is a 50Ω “back-termination” accomplished on a scope probe line?

I've just been watching Jim Williams' very excellent video on Measuring Switching Regulator Noise. At 1:58 Jim mentions a "50Ω back termination" in the probe setup that looks something like this (but ...
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0answers
48 views

Can I make a discharge curve for a galvanic cell

Can I make a discharge curve for a aluminum-hydrogen galvanic cell? I made circuitry to have constant current as load for the cell (1mA) but my cell went from giving 0.852 V straight to 4.4 mV in a ...
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1answer
133 views

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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1answer
62 views

Is it possible to measure inductance without LCR Meter/OSC/FG

Like the question, i don't have an oscilliscope/Function Generator/LCR Meter. I do have a multimeter and a lot of "scrap inductors" that i would like to measure. I have searched a lot on the web and ...
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5answers
309 views

Testing Chinese CR2032 Li-ion Battery Capacity

I recently bought a lot of cheap CR2032 batteries from aliexpress. Since there is no manufacturer stated on the package or the batteries, I would like to know if these batteries really have 220 mAh or ...
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2answers
131 views

Does it ever make sense to use a 50Ω input with 10X scope probe?

I'm at the point in my learning where one discovers measurement setup for a scope at RF frequencies is quite a bit more involved than I thought :) I see the importance of thinking about the probe + ...
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4answers
764 views

DIY Oscillosope probes

I am interested in making my own cheap (somewhat disposable, or permanently attached to prototypes) probes for my oscilloscopes. In complex circuits, and dense PCBs sometimes it may be difficult to ...
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1answer
67 views

Measuring the inter-winding capacitance of a multi-coil transformer

I want to measure the inter-winding capacitances of a multi coil/winding transformer. (To use them in a simulation) For a two winding transformer I would measure it by shorting out the individual ...
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1answer
113 views

IR2110 - measuring Vb to Vs kills MOSFET

I got a new digital oscilloscope as a gift. As a training course, I observed some waveforms of my test 12V full bridge circuit that is driven by TL494 and two IR2110 operate the IRF3710 100V mosfets. ...
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2answers
416 views

How to measure EMI without special equipment?

I have bought a cheap dashcam to play with, only to discover that my GPS receiver stops working when it's on. After I ruled out power supply issues (both devices have batteries), I'm left with a ...
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1answer
365 views

How to measure power factor cos phi with an Arduino?

according to How does one measure the power factor? I can measure the power factor (cos phi) by comparing the zero point crossing of Voltage and Current. This is clear. The problem I have is what if ...
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2answers
198 views

Which one is more accurate: Digital oscilloscope or Analog oscilloscope?

I know it is some sort of wide question, but nowday I usually only see digital oscilloscopes around. I want to know if their digital nature will affect the accuracy of measurements? (Something like ...
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1answer
50 views

Method and probes for measuring resistance of conductive braiding?

Looking for advice on a method to measure the resistance of a piece of conductive braiding. The braiding is a metal plated material; it's flat when pulled taut and expands into a cylinder when bunched ...
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1answer
355 views

Arduino piezo vibration measurement circuit

I'm looking for a very simple measurement circuit to measure vibrations with a piezo elment and an arduino device. I want to read positive and negative values. I have this sensor: ...
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1answer
70 views

Piezo vibration sensor board negativ values

I have this piezo vibration sensor module from Grove: http://www.seeedstudio.com/wiki/Grove_-_Piezo_Vibration_Sensor Using this sensor and an arduino device I want to measure two things: amplitude ...
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1answer
46 views

What means linear response for accelerometers?

What means that accelerometers measures linear acceleration and, in particular, that they are a linear response?
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1answer
67 views

Low noise amplifier

Recently, I got a low noise amplifier (i.e., ZFL-1000LN+ from MiniCircuits, http://194.75.38.69/pdfs/ZFL-1000LN+.pdf) with two wires already soldered in the turrent terminal pins. Today I have been ...
3
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2answers
109 views

DIY DC Blocking Capacitor for oscilloscope

I'm studying switching converters and want a bench setup that will allow me to reliably observe the various voltage waveforms (output, inductor, switch) on my oscilloscope. I discovered pretty ...
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1answer
95 views

Questions about Dry EEG electrode interfacing circuit

I have finished reading a paper about developing an interfacing circuit for Dry EEG electrodes and there is a few points that I couldn't understand. To mask the diode’s parasitic capacitance and ...
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2answers
119 views

How to measure speed without any mechanical or electrical connection?

I would like to build an as-much-portable device for measuring the speed of a vehicle, to check speedometer accuracy and know the offset if one present. The idea is a cigarette pack sized box one can ...
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1answer
97 views

human weight scale (60-180kg) with gram resolution [closed]

Is it possible to create a scale with a dynamic range of 5-6 figures? (measure the weight of a person in a gram resolution)? If not why? If yet, how?
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1answer
50 views

grounding measurement methods

As long as I know the accepted methods for measuring the resistivity of electric grounding grids, once they are built, for any kind of building (in cities, at industrial level, transmission towers, ...
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1answer
100 views

How does capacitive EEG electrodes measures EEG signals

I have read the following sentences from an article: The effect that there are also charge displacements on the body surface due to brain activity is used for the capacitive measurement of the ...
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2answers
47 views

Where should I look for transformer inductance discrepancy?

I'm experimenting with this smallish (~15VA) toroidal line transformer as a "lab" exercise as I'm learning about transformers. Right now it has its original 115V primary winding only; I "unwound" and ...