# Tagged Questions

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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### Measuring the voltage between (positive/negative) terminals of PV cell and ground

I tried to measure the voltage between positive/negative terminals of a PV cell and ground while the cell was exposed to the sun, I found that the voltage decreases with time -the PV cells were ...
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### differential pressure sensor gives oscillated result

I'm trying to measure water pressure of water pipe by exactly replicating this : http://www.practicalarduino.com/projects/water-tank-depth-sensor When I tested the sensor (by leaving both inlet free, ...
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### LCR Meter Methods [on hold]

I am to design a LCR meter for my graduate project with STM32 MCU. The resistance I am aiming to measure will be between 10 ohm and 1M ohm. So far I have tried using voltage divider method, however ...
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### How to monitor temperature of an area? [on hold]

What is the proper non-contact way to monitor the temperature of an surface area? In the picture below, I divided a square into 36 little squares. The goal is to get the temperature of each and ...
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### Precise short distance measurement using RF [closed]

I am new to this so please bear with me. I have a small project and need to measure the distance between 2 objects with a resolution of 1cm (max distance between objects would be 1-2m). I thought of ...
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### Measuring phase difference between digital signals

I have been struggling for some time to come up with a meaningful way to test the phase difference between two quadrature channels of an encoder. I have access to a DPO 2014B Tektronix scope and have ...
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### Voltage measurement circuit

I have a material and I want to measure the voltage and current through it over time. Unfortunately I only have an automatic voltmeter and the resistance of the material changes over time. Because I ...
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### How does this current sensor work? (with only half magnetic core)

I have been working for sometime with current sensors (current sensor goes all around the conductor to get a voltage reference corresponding to the amperage), however i just found this little device ...
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### Voltage reference sampled by ADC (12 bit) gives value that is off by more points than other measurements

I am using the TI REF3020 voltage reference (2048mV) in combination with a microcontroller in order to have a reference for voltage measurements. The microcontroller is powered by 5V (5.00V), the ...
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### How to calculate correct value of capacitor C2? [closed]

I have the following connection, what should be the correct capacity of C2, for the case when the device is turned on, so it will load untill my MC will be not ready? Thanks
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### Oscilloscope probes, measurement

I'm new to electronics and have a question about oscilloscopes, if I understand this correct when attaching probes, one of the leads of the probe needs to be grounded, my question is why? Can't I use ...
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### minimum detectable signal of an IMU (MPU 6050)

I want to work with the MPU 6050 IMU, but before I have to check, which minimum detectable signal the IMU can measure or rather what is the lowest change of angle the IMU can measures. I have the ...
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### Data logging over 5km range [closed]

I am working on a project of designing a system for leak detection in pipelines. I want to monitor pressure/flow in both endings of a 5km long pipe and acoustic emissions onto some crucial points of ...
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### Insertion loss requirements for 100BASE-TX

I'm evaluation an insertion loss measurement of a transmission line for 100BASE-TX and have turned to the specified requirements in the IEEE Std 802.3-2012 for guidance. There I stumbled over ...
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### What is the difference between Fidelity and Dynamic Error in Dynamic Response?

I am really confused in these two terms. According my lab manual Fidelity is defined as the degree to which a measurement system indicates changes in the measurand quantity without dynamic error. ...
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### How to obtain the widest pulse on an oscilloscope?

I need to get the widest pulse from a train of pulses. In some tester you have the option to show only the highest measure, There's a way to do that with the pulse measure in a DSO? The DSO is an ...
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### How to extract complex permittivity from a CV measurement?

I can choose from the following measurements: Z, theta (impedance and phase angle) R + jX (resistance and reactance) Cp-Gp (parallel capacitance and conductance) Cs-Rs (series capacitance and ...
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### Measuring RF and heterodyned frequencies

I have a question about RF measurement techniques. The partial schematic above is the front end of an AM radio receiver kit. I have assembled the kit. The kit manual states, Transistor Q7 not only ...
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### How to trigger a sampling oscilloscope on a PAM-5 signal

I am trying to acquire an eye diagram on a Gigabit Ethernet (PAM-5) signal, measuring differentially over pair 1. I am using a Tektronix DSA 71254c. I have not been able to successfully configure the ...
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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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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 di-...
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### 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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### 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: http://www....
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### 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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### 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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### 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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### 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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### 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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### 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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### 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 ...