Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [power-meter]

83 questions
24
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5 answers

Circuit for measuring high voltage DC voltage (up to 1000V)

I am a final year E&E student and I am trying to built a power meter that must be able to measure quite high DC voltages, up to 1000 V DC. I am measuring with a simple 12-bit ADC that has an input voltage range of 0 - 2.5 V. Would a simple voltage…
Eduan Shuda
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2 answers

How does this iPhone app measure the power flowing through an AC appliance cord?

My electric utility released an iPhone app called "DTE Insight" which (among other things) measures the amount of power flowing through an appliance's power cord by asking you to hold the cord against a specific part of the iPhone at a specific…
Juffo-Wup
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11
votes
6 answers

Arduino power meter

I want to create a power meter and use arduino to log the info and send to the web. Is there any easy solution to the power meter? I live in Argentina and the power line is 220V. Thanks
Mariano
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10
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8 answers

If the energy meter sees a reactive load, will it register a lower reading?

At an exhibition on home appliances, I saw this guy hawking his 'energy saver device'. The guy claimed that merely plugging his instrument into the supply would reduce the consumption reported in an energy usage meter by a fourth. He mentioned…
Everyone
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9
votes
7 answers

Best shunt resistor for power meter application?

Looking for a shunt resistor for measuring power usage and was wondering if anyone had any experience with these. It should be capable of handling 110V/20A in-home circuit. EDIT: Energy monitors are the rage these days and I was thinking about…
jdiaz
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8
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3 answers

Battery level - how to check

How can I check the level of charge left in a battery?
oneat
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7
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5 answers

How does a bi-directional electricity meter know import from export?

I've searched everywhere for this but can't find the answer... Its possible to have 3 phase electricity meters that measure both imported and exported kwh with each value being recorded in separate registers. How does the meter differentiate…
dazza
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5
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How to calibrate a Kill A Watt meter and understand its hidden service menu

I found a hidden menu within the Kill A Watt P4400 meter, which is accessed by holding down the Volt and Hz buttons. Although I rendered my meter unable to measure accurately because of my futzing around with the menus, I was able to derive…
bwDraco
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5
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3 answers

What do the stars in a power meter symbol mean?

Sometimes I see stars in a power meter in three-phase circuit are drawn as below. What do the stars in a power meter symbol mean? There is another example here (page 14/20): Now it seems to me that they are dots to indicate the polarity of the…
hana
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5
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3 answers

My IC keeps blowing up - PAC1720 current sense IC

I am using a PAC1720 current measuring IC to measure the current/voltage/power being delivered to a lead acid motorcycle battery that is being charged. Here is a newer datasheet and an older datasheet (with different info in them!) Everything seems…
macdonaldtomw
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5
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Can adding inductive load really reduce mains power consumption?

I have recently bought one of the cheap mains power meters (EL85-2042A to be precise) to monitor power consumption. It's really helpful when I need to know where my electricity bill comes from, or when I want to make sure I switched everything off…
Dmitry Grigoryev
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5
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2 answers

How can I disassemble an iPhone 4 battery without damaging it?

I would like to measure the power consumption of an iPhone 4 using a source/measurement unit. On other devices I am able to connect the SMU directly to the +/- battery terminals, using tape to insulate the +ve battery terminal from the SMU's supply…
rupello
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5
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5 answers

Can single clamp measure total current from 3 wires?

Single AC clamp can measure current flowing through a single wire in a non-invasive way. There are AVR/Arduino projects use such a clamp to measure house power usage. However, they use 3 clamps for 3 main wires that come into house breaker box.…
avra
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4
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2 answers

Measuring the Current Draw from a LIPO Battery

I have been working with LIPO batteries to power my portable projects for a while (mostly in RC aircraft), but when using them, I have always had to guess as to how much charge is remaining. Now, I am trying to build a system to provide a more…
topherg
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3
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2 answers

What is "transformer connected" vs. "direct connected" for a electricity meter?

I am looking at sub electricity meters. Right now I am reading about the ABB product line EQ. In the documentation (link to PDF, "Electricity Meters - For modular enclosures and DIN rail"), they split the products into two categories, the ones that…
Mads Skjern
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