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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0
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0answers
19 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
126 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
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1answer
112 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
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2answers
52 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
51 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
51 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
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3answers
84 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
84 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
270 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
76 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
38 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
votes
2answers
37 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
33 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
votes
2answers
77 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.
0
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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
55 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
votes
1answer
37 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 ...
1
vote
2answers
100 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 ...
0
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0answers
28 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
171 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 ...
1
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3answers
91 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.
-1
votes
1answer
69 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
316 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
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2answers
80 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
votes
1answer
72 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 ...
1
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1answer
104 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
vote
1answer
153 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
75 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
votes
2answers
106 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
198 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
63 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 ...
1
vote
2answers
138 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
vote
2answers
109 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 ...
1
vote
6answers
196 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
223 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 ...
0
votes
2answers
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, ...
0
votes
3answers
397 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
137 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
67 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
votes
1answer
60 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. ...
1
vote
1answer
102 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 ...
2
votes
1answer
77 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 ...
5
votes
2answers
233 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 ...
2
votes
1answer
167 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?
0
votes
2answers
86 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. ...
0
votes
1answer
42 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 ...
-1
votes
1answer
140 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 - ...
0
votes
0answers
53 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 ...
1
vote
2answers
231 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 ...
0
votes
1answer
61 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. ...