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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Do batteries have a delay when adjusting to a new load?

So I am creating a battery voltage measure, and it takes a reading both when the battery is in open circuit, and when it is loaded with a 100mA constant current. I have set it up and the reading is ...
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2answers
49 views

Comparator Output Swing Measurement

i wan't to measure the maximum and minimum output swing of a Comparator. I'm using the circuit which you can find attached. However, since the Output of the Comparator (TI LM2903) is open drain, I ...
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1answer
35 views

Precise Measurement of Noisy Voltage

I'm working on a circuit that will have a current shunt before a device connected to a truck's 12V system. This system can have voltage drift, and large transients during operation. The connected ...
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2answers
73 views

Measuring the resonant frequency of an RLC circuit

I have a simple RLC circuit (100 ohm resistor, 10mH inductor and 1uf capacitor in series) and I need to measure the circuit's resonant/natural frequency and damping coefficient. The input to the ...
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0answers
21 views

Op Amp Servo Loop Auxiliary Amplifier

I'm planning to build a op amp servo loop for op amp measurement. (see http://www.analog.com/library/analogdialogue/archives/45-04/op_amp_measurements.html) Does anybody have experience with the ...
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1answer
155 views

What is the need of Neutral and Phase Metering?

I'm working on a project where I have to implement a metering IC to measure Voltage, Current and Power on 230v power lines. I have to use Atmel's 90E24 single phase metering IC. This IC has two ...
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3answers
47 views

Definition of Full-scale error

I was looking for the concept of "Full-scale error" (related with laboratory measurement terminology) on the web without success. I would appreciate your help.
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1answer
47 views

Measuring pulse using an EMG device

For another project I once bought the following EMG sensor kit: https://www.sparkfun.com/products/11776 Now, I would like to know if it is possible to measure the heart pulse using that EMG sensor ...
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3answers
289 views

How to sense wind direction - low cost, low power

I need low cost wind direction sensor. Requirements (edited) low power low cost ($5 or less) wide temperature and humidity range (it will be part of weather station) at least 5 degrees acurracy and ...
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2answers
58 views

How to hook up a load cell to an Instrumentation amplifier correctly

I am trying to get load cells connected to an instrumentation amplifier. The load-cells I have are extremely similar to the ones here https://www.sparkfun.com/products/10245. They have 3 wires coming ...
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1answer
67 views

Nature of noise gotten from digital oscilloscope

I've got strange noise while using digital oscilloscope (Auris B-424). Spectrogram of this signal presented on this image: (X time in seconds, Y frequency in Hertz, in this image case from 0 to 50 ...
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1answer
102 views

How is line voltage measured?

When people say that the line voltage in the US is 120 volts, do they mean amplitude, Vpp or Vrms?
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1answer
141 views

Is this current measurement solution okay?

One wishes to measure the RMS current (12A max.) drawn by an AC motor using a PIC16F887 at intervals of 1 second. One cost effective solution I am considering is using a current transformer, a bridge ...
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68 views

What influences capacitor maximum current handling?

In this answer it is said that the maximum capacitor current handling is "largely a mater of losses", what I can understand that is a factor for maximum dissipation. So, what is the thermal ...
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2answers
92 views

Eye diagram test

I am trying to perform a eye diagram test on a device to check its USB performanance. I am using a board "SQIDD" in order to perform this test. The following figure shows my test setup, I am using ...
7
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1answer
190 views

What does sequences like 1-3, 1-10, 1-3-10 etc in a spectrum analyzer mean?

I have read in a paper explaining spectrum analyzer basic 'When selecting the RBW(resolution BW), there is usually a 1-10 or a 1-3-10 sequence of RBWs available. More RBWs are better because this ...
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1answer
56 views

Combining ±% with ±dB in measurement uncertainty

Firstly apologies if this is not the correct place to post this but wasn't sure which site would be good to ask regarding about measurement uncertainty calculation. I am trying to calculate the ...
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2answers
126 views

Loop count in a current transformer

I was reading this article about current transformers. It says that, the loop count is 1 when the wire is just passing through the core. And there are 2 loops when it is wound for once, and 3 loops ...
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2answers
84 views

Get motor ratings from unknown DC motors

I've purchased bulk cheap DC motors for a robot problem. But I don't know their ratings. Is there a way for me to find out? For instance, I would like to know their max DC voltage input using basic ...
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6answers
173 views

Measuring small inductances

I'm working on a small hobby project - a small (230V wall plugged) coreless induction furnace. I generally know what I'm doing, chosen a topology, calculated inverter and coil parameters, desired ...
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2answers
159 views

Multimeter input impedance and its effect on the measurement of charged capacitor's voltage?

while experimenting with capacitors, I charged a 15pF cap through a resistor to the voltage of a 1.5v battery. Then when I disconnected the capacitor and tried to measure its voltage with a 10Mohm ...
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46 views

Measuring the change of angle on any plane

I've been trying to come up with a system to measure the change in angle on any plane. So basically I hold up my electronics board in some kind of angle, click on a button to reset the measurement, ...
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3answers
313 views

RPM counter using 8051 microcontroller

I am building a RPM measurement unit using 8051 micro controller. I want to measure RPM of AC motor. I have connected proximity sensor to get the pulse for each turn. I have connected the proximity ...
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2answers
124 views

How to reduce op amp output error?

I am trying to precisely measure cell voltage of a LiPo battery using a differential amplifier. The idea is to use an op amp to measure each cell voltage. I need to get a precision of about +-5mV ...
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1answer
60 views

Measure Power Supply Noise Rejection at MHz and GHz

I'm trying to characterize the performance of a power supply module, one of the criteria being power supply noise rejection, in particular at different frequencies. For testing 10Hz to 100kHz, I was ...
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1answer
48 views

What is the difference of a loadell input and output resistance?

I am trying to understand the specifications of a load cell and there are the input and output resistance as you can see here, it says 1090±10Ω for input resistance and 1000±10Ω of output resistance. ...
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1answer
91 views

Does this loadcell's creep mean that I can not let a constant load on the loadcell?

I want to build a connected scale that I can set coffee powder (for example) on it and check over the internet how much of coffee I still have without going to see it. Usually all loadcells have a ...
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1answer
73 views

Cheap sensor for measureing air dissolved in water?

I have been experimenting a bit with hydroponics lately, and one of the important things when building a hydroponic system is to aerate the water/nutrient solution. This is usually performed with an ...
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2answers
220 views

Why to use Siemens to measure high resistance?

I have a Fluke 87V and I can see lots of EEVBlog videos were Dave measure high resistance values, and instead of using the Ohms range, he goes to the Siemens range (nS actually). My question than ...
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1answer
132 views

How to measure ESR

I have a bunch of capacitors but no clue of what ESR they have. Is there a way to measure the ESR? Can I set up a test circuit to measure it?
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2answers
84 views

Measurements with multimeter giving paradoxical values

I study civil engineering (majoring in electrical engineering) and part of the program in my university is a design project. For this project my team developed a PCB and naturally it was full of bugs. ...
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1answer
41 views

Measure/Access Information from small device through audio jack (mic)? [closed]

I've got a small device that I have not yet opened. It sends some unknown sequence of voltage and current through a medium for a few seconds thereby calulating and then displaying a result value on a ...
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1answer
136 views

What is the difference between Pack- and Bat- on a LiPo Battery

I am trying to figure out how to use the TI bq34z100 to measure the charge in a 29.6v 8s1p 5.4Ah pack. Out of this pack I have A charge connector with + and - and a discharge connector with + and - ...
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50 views

How to measure force on line

Trying to figure out how to measure force on a string which is being pulled. I can't attach it to anything and the force is great enough to cause it to unravel from a spool. Was thinking of ...
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2answers
193 views

ADC & sensor calibration

I have a scenario that implies measuring 2 inputs: - voltage through a resistive divider - current through a hall sensor followed by opamp for offset, direction and scaling In my software, each ...
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1answer
59 views

Bipolar Transistor PTAT Cell and setup

I am in a measurement systems class at school, and we have a project to design a measurement system. I was reading my text book when a diagram caught my fancy, and I thought I would try to build it. ...
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1answer
91 views

Significant figures on component's values

I'm reading a book where resistor values are discussed: I did not understand about how 3 significant figures can cover uncertainties from 1 to 0.1 % as stated in the 1st paragraph 6th line of the ...
3
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2answers
146 views

How can I multiplex my oscilloscope probes?

Let's say that I'm tasked with the job of measuring the propagation delay of each inverter in a 7404 hex inverter. I've got a pulse generator, a power supply, and an oscilloscope with two probes, so ...
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2answers
407 views

Measuring average current with uC and current shunt

This is my first post. I'm a software guy trying to do hardware so be gentle :) Circuit I'm designing a small circuit (see pic, and sorry for messy schematic) that plain and simply is a bunch of ...
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0answers
142 views

Measuring radon levels

I saw a commercial full built sensor/alarm which can measure it but I cannot find any IC with that function. What is the type of component to use to measure radon level in the air?
2
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1answer
236 views

How to measure weight?

Last few months I am working on personal project -- I want to measure weight of beehive during the year and then save the results. Beehives has usually from 100 to 200 kg and during one day, the ...
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1answer
91 views

Interfacing with the MLX91206

I am planning on using an MLX91206 to measure the current draw of a set of Peltier elements. They draw up to 17.3A at 24V. However I would like to measure their current draw without interfering by ...
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1answer
63 views

Thermocouple on a grounded stainless steel box

My present project is a ~6kW switching converter in a sealed stainless steel box. The box is grounded well. When I put a thermocouple on the surface of the box, the reading is noisy. Even if I put ...
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2answers
228 views

Wheastone Bridge vs. voltage divider [closed]

I read that Wheatstone bridge is more sensitive than voltage divider, since it acts as a DC offset removal circuit. But I can't understand why ?
2
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1answer
119 views

MPX2100DP only measures depression

I'm trying to read out the analog differential pressure sensor MPX2100DP. In my first approach I used an oscilloscope to visualize the change of voltage. My basic setup was only the sensor connected ...
3
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2answers
218 views

Ceramic capacitor value changes after soldering!

I am debugging a power amplifier circuit and trying several capacitors values to fine tune the design to meet the frequency response specifications. All the 0603 and 0805 ceramic capacitors are ...
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2answers
171 views

How accurate is a ripple counter (using D flip-flop) in measuring the frequency of a signal?

I have two oscillating signals S1 and S2 whose periods are always different by a very tiny amount (~10-50ps). Can I use a D-flip-flop ripple-counter to measure S1 and S2 individually, and then ...
2
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1answer
73 views

Understanding crystal resonator symbols - which one is 24Mhz?

So, I'm in need of a 24MHz crystal to drive an AVR microcontroller. I've got some crystals that I've desoldered off some old, useless equipment. I've found three crystals that have '24' on their ...
2
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1answer
93 views

Weird Voltage measurement problem

I have a DC/DC converter outputting 5.18 VDC @ 25% load (1 Ohm resistor). If I measure the voltage at the green nodes it fails out of tolerance, if I measure the voltage at the red nodes (before the ...
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2answers
1k views

Why do measurements displayed in multimeter inconsistently vary by factors of 1000 depending on range?

For my science fair project, I am measuring the resistance of a 100 foot piece of 32 gauge Nichrome wire. Using a Innova 3300 digital multimeter, I get the following results for each resistance range ...