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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3answers
237 views

What is the test voltage of a ohmmeter?

Ohmmeters don't appear to make LEDs conduct which gives overestimates in the resistance measured (tested with a R1//(R2+LED) parallel circuit). So what is the voltage they apply to the circuit, ...
0
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1answer
53 views

How to measure power/energy with analog circuit?

I would like to measure either power (running average, for example exponential average with a certain time constant) or energy (power integrated over time) with an analog circuit. The setup I have ...
1
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2answers
59 views

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 cathegory of methods one can include the ...
1
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0answers
14 views

Sony Ex Data Acquisition Frontend

I am looking for information on a third party driver for the Sony EX-IF10 data acquisition frontend. I know sony made drivers for Matlab and Labview as it was advertised in promotional materials. ...
1
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1answer
98 views

Why not use audio codec chip as measurement ADC/DAC?

I am working on a project that needs simultaneous ADC/DAC. The specs of the on-board ADC in typical microcontrollers are pretty weak, and separate ADC with good specs are much more expensive than ...
6
votes
1answer
515 views

How to set the oscilloscope to measure potential between two points that aren't ground?

We have to measure the voltage across a-b in this circuit with an analog oscilloscope, but neither of these points are grounded. How should we put the channels of oscilloscope to perform the ...
0
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1answer
90 views

Why does the GND of the Arduino oscillating as well?

I have an Arduino Uno and what it does is simply output an oscillating signal of 1 MHz on PIN11. I measured the signal using a oscilloscope and a probe with a ground clip. First, I connected the probe ...
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0answers
26 views

How do you measure a distance along the Z axis in Altium?

If you hit CTRL+M, it's easy to take a measurement along the x or y axis. If you want to measure along the Z axis (for instance, the height of a 3D body), how do you do it? I googled "measure the ...
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1answer
82 views

resistance measurement problem with digital multimeter

I accidentally caused a short circuit with DMM common lead while measuring 220 AC voltage. then when I tried to measure resistance it gives me a reading of 3500 ohm while there is no resistor ...
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0answers
23 views

Implementing Peltier temperature controller in a circuit

I need to measure the temperatures of semiconductors using a Peltier temperature controller. I am using a DT9818 (it's a USB collection board from what I have learnt). I would need to use software ...
2
votes
3answers
142 views

How to identify if noise is coming from circuit or scope?

Occasionally, I'll be probing a circuit and would expect to see something specific and sometimes I see either crap or the signal im expecting with crap. This video from EEVBLOG is a good example of ...
1
vote
1answer
118 views

Can I increase inductance using permanent magnet ?

I know that when I insert a ferromagnetic core inside an air-cored coil, the inductance increases. What if I inserted a permanent magnet with a cylindrical shape into an air-cored coil, does the ...
3
votes
2answers
59 views

How to measure coils without Inductance measuring device?

I have a multimeter that can measures Capacitance, Resistors, voltage and current. If I have a known coil and unknown coil. Can I measure the ratio between the inductance of the two coils ? Is it ...
2
votes
2answers
61 views

Do LED and photodiode rise times matter for time-of-flight (TOF) measurement?

Do I need small rise times of an LED and a photodiode/APD when considering time-of-flight measurement? Given I know rise time of both diodes I am always able to count time of flight by subtracting ...
0
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2answers
58 views

Measuring internal resistance of a battery while it's being charged

I was startled to hear that there are devices out there that can measure the internal resistance of batteries, in circuit, while the batteries are being (trickle-)charged. For example, Hioki markets ...
0
votes
3answers
94 views

Very wide range high voltage measurement with optical isolation

I have a voltage source I'd like to measure, it is from 0V to 1kV, any value in that range. The accuracy isn't that important, but measuring with an accuracy with 1-5% would be perfect. This has to be ...
0
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2answers
90 views

How much power does a GPU actually use when only doing PCIe I/O, or only compute?

I hope this is the right sight to ask such a question, if not please be kind and direct me elsewhere. I have some discrete GPU with a TDP figure of X watts. Now, sometimes the GPU does Only ...
1
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2answers
277 views

How to measure current practically in a circuit

I have to measure this circuit, I have done the theoretical calculations using Kirchhoff's 2nd law, but I'm having troubles in measuring the current in each part of the circuit: I have to measure ...
0
votes
1answer
100 views

Measure LPG (LP Gas) level using an ultrasonic sensor. Which sensor?

I need to measure the liquid level of LPG through a thick 4000/8000/45000 stationary tank. They already have flowmeters but they are easily tampered. I need to be able to know how much Gas is in the ...
1
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0answers
42 views

Li-SoCl2 battery state of charge

I'm developing a data logger powered by Li-SoCl2 (http://www.100y.com.tw/pdf_file/02-SAFT-LS33600.pdf) battery and I have no idea on how to overcome the problem of estimating the residual charge of ...
0
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2answers
38 views

Measuring band-limited noise coming from an amplifier

I have a strain gauge amplifier and from my analysis, it will produce a low level of white noise above approximately 1kHz i.e. the power spectral density is flat above 1kHz. If I measure the output ...
0
votes
1answer
36 views

Help understanding onboard power supply measurement test connections

I recently came across this circuit for measuring the output of a TPS54620 switching regulator (12V->3.3V). I'm not a power engineer, so I'd like some help understanding the parts in red boxes ...
-2
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2answers
80 views

Can we measure a electricity? Embedded System? [closed]

Checking if electricity is passing through a wire or not using embedded systems. I want to check if power is there or not. I am new to embedded system. If yes how can I check.
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2answers
71 views

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 ...
0
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2answers
58 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 ...
0
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1answer
38 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
133 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
31 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 ...
2
votes
1answer
177 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
123 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
79 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 ...
6
votes
3answers
342 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 ...
0
votes
2answers
113 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 ...
0
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1answer
73 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
106 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?
1
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1answer
173 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 ...
0
votes
2answers
76 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 ...
0
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2answers
122 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
votes
1answer
204 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 ...
2
votes
1answer
70 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
159 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 ...
1
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2answers
129 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 ...
2
votes
6answers
235 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 ...
1
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2answers
271 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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2answers
47 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, ...
0
votes
3answers
469 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 ...
1
vote
2answers
157 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 ...
3
votes
1answer
74 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 ...
0
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1answer
80 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
112 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 ...