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Questions tagged [power-measurement]

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43 views

Accuracy on wattage measurement: multimeter+formula or wattmeter [closed]

Which tool that have more accuracy on measurement of a resistive load ac sinusoidal wave?
28 views

Power Measurement of AC diesel generator

I want to measure the real power of an AC diesel generator which powers some load. There are two such channels and the maximum power is 10kW. The sampling rate must be 1 sample per 10ms and I want to ...
929 views

Can I measure torque accurately by an electrical or electronic method?

I am a Btech. student from India. We have been given a project in which we have to design a micro-torsion testing device. We are planning to clamp the specimen and rotate one end by fixed angles ...
27 views

Successive Detection Logarithmic Amplifier

let's consider this logarithmic Amplifier: I do not understand why at the terminal LOG OUTPUT there is a current which is proportional to log(Vinput). The current flowing on each diode is equal ...
43 views

Measuring Current by rectifying or voltage-doubling a Current Transformer

Originally, my plan was to just get the voltage output of a current transformer (obviously with the burden resistor circuit stuff and DC biasing circuit stuff) before ADC'ing it, averaging it’s output ...
44 views

How could I measure RF transmission power from SMA connector without having a RF wattmeter equipment?

I need to measure the RF power of a radio transreceiver, and since I haven't specific RF wattmeter equipment, I'm wondering how I could do this using a classic multimeter. I would avoid to ...
63 views

How much power does a “smart meter” use? [closed]

How much electrical power does a typical domestic “smart meter” use on average, in watts, for its own operation? I have searched the internet for an answer to this question but have been unable to ...
45 views

Readings for a current transformer reversed

What would happen to the measured values of a circuit (real power, apparent power, power factor, current) if I install a current transformer "backwards"? Usually a current transformer has some ...
62 views

Fast 5V DC power monitoring

I am designing a camera that is powered by a 5 V DC power line. I need to evaluate the peak power consumption of the device during image capture. At a pixel clock period of 40 microseconds I expect ...
62 views

Measure low AC Power consumption (oscilloscope? MCU?)

I would like to measure AC power consumption of devices such as AC/DC charger, AC LED bulb or an electric circuit in the main box of a house. However, their power consumption are quite low and the ...
152 views

How to measure micro watts (uW) [duplicate]

In an extreme low power project (MCU+BLE SIP running on a CR2016 battery for year(s)) I would like to measure the power consumption under different environments/algorithms. What would be the correct ...
192 views

How does a Hall-based wattmeter work?

I read about the Hall effect and understand its usage in sensors like speedometers, but I also read it can be used as a wattmeter. How can it happen? In order to calculate power (P) we need to ...
86 views

Low pass filtering effect on accuracy of power measurement

I'm planning on measuring consumed power (for an e-bike) by sampling current and voltage with an ADC and digitally approximating the power based on the obtained values. I need to pick a sampling rate ...
36 views

Is it necessary to cut off PV from grid before measuring its power output?

I need data of Power output from PV in one day. I was told to cut off the connection from PV to the grid also because the measurement is from the inverter, I also need to change the phase into 1 ...
73 views

Measure ~300kHz Induction Heater RF Power

I have been tasked to gather data from an old running 335kHz 5kW induction heater system. It has no outputs available to give amperage, power etc. Basically there is an assumption that the unit is not ...
61 views

Spectral analysis of spectrum analyzer

Using measures from a spectral analyzer, I am a bit confused on how to properly compare the power of each spectral line with the fourier coefficients (Parseval). Take this signal: Take it's spectrum:...
149 views

Power meter current transformer: possible to sum mutiple phases

I am currently looking at this inexpensive power meter modules with TTL interface. It seems to use internally the same ASIC as many chinese wall-wart power meters: It comes with a current transformer ...
67 views

What is difference between channel power and normal power plotted by a spectrum analyzer?

I want to measure the power received by an antenna from an energy source by plugging the antenna to a spectrum analyzer (SA). What makes me confused is that there are different kinds of power that I ...
562 views

Current Transformer (CT) and Potential Transformer (PT) Sensors - How to Measure Electrical Power Usage?

I am not from Electrical Engineering background and so, does not have much idea about how energy power meters work. I want to measure electrical power usage of a three-phase induction motor. So, I ...
365 views

What is the correct way to measure DC power at the output of a boost converter in a Simulink simulation?

I modeled a DCDC boost converter, and I would like to measure the power at the output of the converter, I do not understand much about simulation times, sampling, and this sort of thing, so I do not ...
63 views

Is the gain from IIP3 curves wrong?

Suppose I have an unknown system and I would like to know its linearity. I am confused by the proper measurement of the IIP3. The gain is defined as "total output power" divided by "total input power"...
85 views

Can we assume 230VAC in 3 phase system between phase and neutral?

If all devices connected to a 400V 3 phase power system are balanced and have a perfect power factor, can we assume the voltage between each phase and neutral is 230V? Why: I want to measure real ...
132 views

Tool for measuring Real and Reactive Power [closed]

I am currently doing a project where I need the Real power (P) and Reactive power(Q) measurement for a Refrigerator. I understand that if I can measure AC Voltage(V) and AC Current(A) for the ...
353 views

Simplest way to measure 4 cell LiPo battery State-of-Charge during discharging

For testing purposes, I need to know an aproximate percentage of the battery charge in order to know when the battery must be recharged. It doesn't need to be accurate at all, p.e. a simple signal (...
122 views

Precision of estimating power consumption with a current sensor

When estimating power consumption with a current sensor, what is the usual precision that can be achieved for home appliances? I'd like to make a simple circuit using such a sensor and a ...
174 views

Measure current ripple over shunt, legit?

I'm thinking of using a calibrated shunt and then measure the current ripple by measuring the voltage over the shunt, with an oscilloscope. I'm assuming a differential probe would be the best choice ...
40 views

compact headless energy meter [closed]

I'm looking for a way to monitor the power of several circuits at home: Washer, dryer, freezer etc. I already have a modbus meter for the heatpump, but I don't have room for an extra meter on the DIN-...
185 views

Calculation of active power and apparent power through sampling

I'm currently working on a power meter device based on simultaneous sampling of current and voltage values, I intend to use this system to measure the active, reactive and apparent power on a non-...
838 views

Why the difference between the RSSI and Rx Level measurements is so big?

I'm new in Telecom. Today, I downloaded the Android APK called "Network Cell Info Lite". In my house, I got this measures: RSSI: -51 RXLEV: 60 I know this measurements represents the received ...
115 views

How to calculate 50Hz active power measurement accuracy from datasheet?

The R&S HMC8015 power analyzer datasheet and technical data list: Range configuration ...
160 views

Electricity Energy/Power measure with Different power factor

I am designing a circuit that measures the energy consumed from 50Hz AC supply (error must be < 1%), by measuring the voltage through potential divider; and current from shunt resistor. Then these ...
140 views

Pulse width discrimination and measurement

I need to measure the time period between points A and B of this signal. The trace is 5 volts/div and 1 sec/div. There are 20 to 50 seconds of "noise" from point B ta A. The time between A and B ...
298 views

how to sense high frequency current and power sensing

Input AC Voltage: 250V Current:2A Max Max Power out : 300W AC frequency : 4MHz Problem Statement is to measure power and sense current and alarm if exceeds certain limit my approach : step ...
249 views

Measuring power factor on sinusoids

I'm not sure if this is the best forum for this or whether stackoverflow mightn't be better, but I'll ask here and see what people think. I have a system measuring 50Hz voltage and currents at 1kHz. ...
4k views

Ways of estimating phase shift

I have a system that's sampling two 50Hz sine waves at 1kHz. What's the best way to estimate the phase shift between the two? The measurements are somewhat noisy and the sampling period is not very ...
2k views

How much power (in watts) can I get from my house outlet?

Suppose I have a PV panel. On it's peak time it produce 7 A with 14 V. So to find out how many watts I get from it I would simply apply this formula: $P = I \cdot V$ So, by applying above formula: ...
44 views

V-meter's value is stabilizing when measuring

I am curious about my V-meter behaviour. Sometimes when I measure voltage the voltage showed by V-meter is slowly dropping until it stabilizes after few seconds. And same for current, except current ...
51 views

dB formula when input and output resistances are equal

Why is the equation of dB voltage gain independent of the input and output resistances? Also, please consider reading the paragraph. I'm not able to understand this. Thanks in advance.
2k views

How to measure voltage in a PS/2 keyboard cable?

I have an old PS/2 keyboard, I doing a future project with it, but for now I just want to measure the voltage in the cable. However I don't know how to do it, so let me explain. It's a PS/2 keyboard, ...
308 views

Protection of Energy Meter from 35KV spark

I have been building a prototype of an energy meter for a project. One of the aims of the project is to make sure the energy meter can withstand a 35KV Spark applied to it. I was wondering how this ...
665 views

Measuring relative rf signal strength [closed]

I'm trying to measure the relative signal strength received by a dipole antenna for orientation purposes. I'd like to do so using an ordinary multi-meter. I don't know much about RF circuits, but ...
122 views

Measure electrical consumption from electric panel

I want to hack my electrical distribution board a little, to measure the energy used by each circuit. Thus, I want to use a little arduino or maybe a raspberry pi and plug it to my circuits to take ...
585 views

ADE7953 smart energy metering - how to connect it

I am currently looking for a IC that would allow me to aggregate energy metering data in my house. I came upon ADE7953 chip from Analog Devices but there is no info how to connect it with power source ...
99 views

Single board computer draws 0.22 amps: How to calculate how long a 2400 mAH 3s Lipo will provide power?

I've got a Raspberry Pi 3 single board computer that I'd like use for remote data collection using lithium polymer (Lipo) batteries as the power source. When recording data, my multimeter shows that I ...
1k views

Total power measurement in 3-phase unbalanced delta system

I have a 3-phase system with an unbalanced delta load, as seen in the figure below. I want to measure the total apparent and active power consumption and if possible, the respective power consumption ...
638 views

Calculating power measurement error from V and I error margins

I am using a Yokogawa WT310 for measuring DC power. The manual (available here) says that both current and voltage have accuracy of +/-(0.1% of reading + 0.2% of range). Assume this example setup: ...
870 views

Signal power and spectrum analyzer

I want to obtain the signal power in dBm (RMS) as it would be displayed by a power meter using a spectrum analyzer (in my case EXA N9010A). But one thing makes me confused: The spectrum is a plot ...
80 views

Interfacing a mains referenced AC measurement circuit with a PC

I need to connect an AC mains referenced measurement circuit with a notebook and I wanted to know if its safe to do that without an isolator. The measurement circuit primarily steps down AC voltage ...