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# 📱 ｜ Can you charge your smartphone anywhere, such as street lights, park benches, and bus stops? -China

### Is it possible to charge smartphones anywhere, such as street lights, park benches, and bus stops? -China

If you write the contents roughly
At Yuso Hamahe Forest Park in Beijing, there are benches with the ability to convert solar energy into electrical energy.

What people are most afraid of today is not that they have no money in their pockets, but that their smartphones run out of battery.Smartphone battery ...　→ Continue reading

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### Wikipedia related words

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# Electric energy

Electric energy(Denryokuryo, electric (al) energy)electricity It is (electric power).

## Overview

What is electric energy?electricityIn timeintegralIs what[Note 1]..In addition, the amount of electricity is "electric circuitThere is electricity inwork".In the conceptual system of physics in recent years, the amount of electricity isエ ネ ル ギ ーIt can be said that the amount of electric power is "energy by electricity".

unit

Electric energy is a kind of work, sounit(That is,エ ネ ル ギ ーUnit).International unit system In (SI)Jules (J).However, since "W (watt)" is often used as a unit of electric power (unit of power), joule as a unit of electric energy is "Watts seconds Often referred to as "(W s)" (1 J and 1 W s are equivalent).More practicalWatt hours (W h) andKilowatt hour (kW h) is often used.

Relational expression

For example,DC(Current that does not change with time) I Is time t The work (electric energy) W Then,VoltageThe V , Power P given that,

[W ・ s]

BecomesAlternating currentcircuitThen.loadTo voltage and current depending on the configuration ofphasedifference θ Will occur,Power factor cos θ In consideration of

[W ・ s]

Becomes (dt Is a minute time,dW Is the amount of electricity in the meantime).When we say the amount of electricity in alternating current, this isActive energyOften refers to.In addition, it should be notedInvalid electric energy Q-t (var ・ s) is calculated by the following formula.

[var ・ s]

## Measurement

Electric energyMeasurementto do so,Electricity meterIs used.

Electric energy measurement at home or corporation

Power companyIn the case of business establishments and ordinary households that buy electricity from, electricity meters (commonly known as "electric meters") are installed, and electricity consumption is recorded regularly and charges are charged. Have been charged.

On the roof at homeSolar panel,Wind-power generationThe proportion of households that install equipment to generate electricity and consume it in-house is increasing, and in these households (not only those of electric power companies), the number of households that have their own electricity meters is increasing. It's coming.An increasing number of households are choosing devices that are computer-controlled and equipped with monitors that display information in graphs.It is possible to display the amount of electricity sold, and if you sell electricity, you will earn a certain amount of income, so some people are looking forward to seeing the value of that (the amount of electricity sold) every day.

Smart meterAlso measure the amount of electricity bysmart gridThere is also a movement to build.

Measurement of electric energy of a specific device

In addition, we have a device (so-called "power saving meter" etc.) to help determine power saving by measuring and checking the amount of power used by a specific electric appliance in the home. The number of households is increasing.

"Clamp meterA device called "clamp wattmeter"[Note 2]In many cases, the amount of power can be measured and displayed by selecting the measurement item.

## footnote

note
1. ^ differentialintegralIs in the opposite direction, so the amount of powerTime derivative(= Electric energy per unit time)electricityIt is also a relationship.
2. ^ A tool that can measure current without disconnecting the circuit.It closes and opens like a "ring" or "waka" with your fingers around the wire.ClampElectromagnetic induction is generated and measured using a device equipped with.
Source

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