# Questions tagged [power-measurement]

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42 views

### Power measurement on multiple loads

I'm designing a circuit for driving multiple loads (min. 16, up to 64) like the one shown below simulate this circuit – Schematic created using CircuitLab The input source is from a multi-...
69 views

### What type of circuit or component is used to sample RF power?

I'm building a 2-stage RF power amplifier and I would like to measure the RF power at each stage and report it to a microcontroller on the board: ...
66 views

### Measure power of solar cell with an esp8266

Scenario I plan to buy some bigger solar cells (together around 500 W) and use them to make my electricity bill cheaper. But in order to find the perfect location on my roof before the purchase, I ...
32 views

### Pulsed DC power calculation

I'm trying to measure the power consumption of my device using a shunt resistor. I'm measuring both the voltage over my shunt resistor and the source voltage. With a math function i'm trying to ...
71 views

### Three phase AC power measurement

I am trying to measure the output power for BLDC controller, in order to calculate the efficiency of the controller. I came to know that two watt-meter method is one of the method used to calculate ...
36 views

### Will the measured powers & energies of two 120V circuits == that of the 240V circuit?

I'd like to design a circuit using the STPM34 (2 channel power meter) that can measure either the power and energy delivered on two separate 120V circuits (one circuit Red Wire, other circuit Black ...
53 views

### Current / power measurement using ACS71020

I am having some hard time in understanding and comprehending the value for ACS71020 current and power measurement. In the manual, rms_avg_1 and rms_avg_2 has been mentioned stating that "The ...
62 views

### Is there any device or way to measure how many watts a computer's processor is using? [closed]

I know there's a device to measure how many watts a computer is using, you get an energy meter you plug the computer into it and it tells you But I'm interested in finding out how many watts a ...
131 views

### Measuring nano amp range current consumption

I am looking to buy one of Joulescope, ZS-2102-A (angler circuits) or Otii (QOITech) to measure power consumption and get graphs of current consumption for some low power BLE/WIFI devices. Does any ...
85 views

### Transformers and wattmeters

This is, probably, a very silly question, but I was thinking: If you have a watt meter and you connect a step up transformer with the lower voltage side attached attached to it (both the voltage and ...
49 views

### Understanding IMON and PMON in LT2940

I have two 12 bit ADC-channels that I am suppose to use in order to read measurement pins in lt2940: Imon Pmon To make it easy, I have 16 Vin and want to scale the input so that I can calculate the ...
47 views

### How Power measured by Meters is affected by Harmonics?

I want to know how energy meters (Electro-static or electronic) measure Energy (let's assume power, ignore time) when there are harmonics present. I know what are harmonics, how are they generated ...
161 views

### DDS238 AC Power Meter: how to calculate current power consumption using pulses

I have a DDS238 AC power meter with 2000 pulses/KWh (1p/0.5Wh) and I want to calculate the real-time power consumption and play an alarm if the value exceed a specific value. I'm using an ESP8266 by ...
83 views

### Low Power Inverter Imports Energy?

A lab-sized microgrid (island) has been set up to test some equipment. An inverter+battery is being used as the source, with the inverter operating at very low power compared to its rating. This makes ...
1k 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 ...
52 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 ...
171 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 ...
63 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 ...
64 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 ...
65 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 ...
91 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 ...
286 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 ...
500 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 ...
166 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 ...
141 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 ...
79 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:...
210 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 ...
111 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 ...
823 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 ...
744 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 ...
94 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"...
118 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 ...
164 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 ...
494 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 (...
188 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 ...
278 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 ...
42 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-...
231 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-...
1k 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 ...
149 views

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

The R&S HMC8015 power analyzer datasheet and technical data list: Range configuration ...
265 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 ...
185 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 ...
350 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 ...
365 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. ...
7k 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 ...
3k 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: ...
45 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 ...