Which LEDs are the brightest and most powerful? Power of household electrical appliances

The system of units called SI (abbreviation of the full name in French) is international. With rare exceptions, it is used in almost all countries. In fact, this is a modern (transformed, modernized) version of the metric system that is familiar to us, only unlike it, it is used to measure physical quantities.

The question “how many watts are in a kilowatt”, on the one hand, is quite simple (for those who have not forgotten high school), on the other hand, requires some clarification. This is the author's task.

The prefix “kilo”, regardless of physical quantity, which is expressed as a specific figure or number, means “x 1,000.” That is, 1 km = 1,000 m, 1 kg = 1,000 g and so on. The same goes for power – 1 kW = 1,000 W.

Therefore, in order to understand how many watts are in a kilowatt, you need to multiply them by 1,000. Or, as they say, shift the decimal point in the number 3 positions to the right.

Examples

Often the confusion is associated with the substitution of concepts. The fact is that there is such a unit of measurement as kW/hour. But this is a numerical expression not of power, but of the amount of energy consumed by a device (or group of devices). Sometimes they say - work completed (in any case, it is meant - per unit of time). This is what they measure, installed in apartment or entrance panels.

Example

An electric heater with a power of 2,000 W (= 2 kW) will consume 2,000 x 1 = 2 kW/hour in 1 hour of operation. Accordingly, in 6 hours of continuous operation it “eats” 12 kW/hour (2 x 6 = 12).

How to convert amps to watts

Not every housewife will immediately figure out how to convert amps into watts or kilowatts, or vice versa - watts and kilowatts into amperes. Why might this be needed? For example, the following numbers are indicated on the socket or plug: “220V 6A” - a marking that reflects the maximum permissible power of the connected load. What does it mean? What is the maximum power of a network device that can be plugged into such an outlet or used with this plug?

To get the power value, just multiply these two numbers: 220 * 6 = 1320 watts - the maximum power for a given plug or socket. For example, an iron with steam can only be used at two, and an oil heater can only be used at half power.

So, to get watts, you need to multiply the indicated amperes by volts: P = I*U - multiply the current by the voltage (in the outlet we have approximately 220-230 volts). This is the main formula for finding power in single-phase electrical circuits.

What is current strength:

Converting watts to amperes

Or the case when power in watts needs to be converted into amperes. This problem is faced, for example, by a person who decides to choose a water heater.

On the water heater it is written, for example, “2500 W” - this is the rated power at a network of 220 volts. Therefore, to get the maximum amps of the water heater, we divide the rated power by the rated voltage, and we get: 2500/220 = 11.36 amps.

So, you can choose a 16 amp machine. A 10-amp circuit breaker will clearly not be enough, and a 16-amp circuit breaker will work as soon as the current exceeds the safe value. Thus, to get amperes, you need to divide the watts by the supply volts - divide the power by the voltage I = P/U (volts in a household network 220-230).

How many amperes are in a kilowatt and how many kilowatts are in an ampere

It often happens that on a network electrical appliance the power is indicated in kilowatts (kW), then it may be necessary to convert kilowatts to amperes. Since there are 1000 watts in one kilowatt, then for mains voltage at 220 volts we can assume that there are 4.54 amperes in one kilowatt, because I = P/U = 1000/220 = 4.54 amperes. The opposite statement is also true for the network: in one ampere there are 0.22 kW, because P = I*U = 1*220 = 220 W = 0.22 kW.

For approximate calculations, it can be taken into account that with a single-phase load, the rated current I ≈ 4.5P, where P is the power consumption and kilowatt ah. For example, with P = 5 kW, I = 4.5 x 5 = 22.5 A.

What to do if the network is three-phase

If we were talking about a single-phase network above, then for a three-phase network the relationship between current and power is slightly different. For a three-phase network P = √3*I*U, and to find the watts in a three-phase network, it is necessary to multiply the volts of the line voltage by the amperes in each phase and also by the root of 3, for example: an induction motor at 380 volts consumes a current of 0.83 amperes for each phase.

To find the total power, multiply the line voltage, current, and multiply by √3. We have: P = 380*0.83*1.732 = 546 watts. To find amperes, it is enough to divide the power of the device in a three-phase network by the value of the line voltage and by the root of 3, that is, use the formula: I = P/(√3*U).

Conclusion

Knowing that the power in a single-phase network is equal to P = I*U, and the voltage in the network is 220 volts, it will not be difficult for anyone to calculate the appropriate power for a particular current value.

Knowing the inverse formula that the current is equal to I = P/U, and the voltage in the network is 220 volts, everyone can easily find amperes for their device, knowing its rated power when operating from the network.

Calculations are carried out similarly for a three-phase network, only a coefficient of 1.732 is added (the root of three is √3). Well, a convenient rule for network single-phase devices: “one kilowatt has 4.54 amperes, and one ampere has 220 watts or 0.22 kW” - this is a direct consequence of the above formulas for a network voltage of 220 volts.

Andrey Povny

Watt (Watt, W) is a common unit of measurement of power. IN international system SI units (SI), watt (abbreviated as W) refers to derived units. Very often, when making calculations and in everyday life, it becomes necessary to convert kilowatts into watts and vice versa. In fact, translation is not difficult, but some people find it difficult to do simple calculations. That is why in this article we decided to describe in detail how many watts are in a kilowatt of electricity.

Power unit ratio

As we have already said, Watt refers to derived units, from which it follows that the value of this quantity can be expressed through the basic units of the system. According to the basic definition, 1 watt is the power that does 1 joule of work in 1 second. Based on this, the representation of the power value of 1 watt using basic units of measurement is as follows:

1 watt = 1 kg m 2 /s 3,

In addition, W can be expressed using other units of measurement:

• 1 watt = 1 J/s, (1 joule per second);
• 1 watt = 1 N m/s, (1 newton per meter per second).

For comfort practical application units of measurement, in the international system it is customary to use prefixes that determine the decimal multiple in relation to the original value. One of these prefixes is “kilo”. This word derived from the Greek “chilioi”, which means “thousand”. Thus, the use of this prefix means that the original value must be increased by 10 3 times.

The formula that determines the relationship between power expressed in kilowatts (abbreviated as kW, kW) and W is as follows:

1 kW = 1 ·10 3W(1)

It is customary to denote the power of many machines and units that surround a person in everyday life and at work in kilowatts. Electric stoves, kitchen electrical appliances, household air conditioners, washing machines, vacuum cleaners - this is an incomplete list of devices on which you can see the designation of rated power in kW. This also applies to internal combustion engines of modern cars. True, here, along with the value in kilowatts, there is often a designation of power in horsepower. The use of this non-systemic unit is nothing more than a tribute to tradition, dating back to the emergence of the first steam engines, which replaced horse traction. To help you understand the relationship, converting kilowatts to horsepower is quite simple:

1 kW = 1.36 hp

Thus, the short answer to the question posed in the title of the article can be formulated as follows: there are one thousand watts in 1 kW. The relationship inverse to formula (1) can be written in the following form:

1 W = 1·10 -3 = 1/1000kW(2)

How to convert kilowatt to watt? To do this, you need to multiply the number in W by 10 -3, that is, divide by 1000. In order to carry out the reverse conversion from kW to W, it is enough to multiply the number of kilowatts by 10 3, or multiply by 1000.

For convenience, we present to your attention a table with which you can quickly convert watts to kilowatts and vice versa:

Translation examples

To make it clear to you how to convert kilowatts to watts and back, we will provide several simple examples from life.

Example 1. The nameplate of the electric motor indicates a rated power of 1.5 kW. It is necessary to determine how to convert the power of a given engine into watt. In accordance with the above, we multiply the number of kW by 1000:

P nom = 1.5 (kW) 1000 = 1500 (W).

Example 2. The technical data table for an electric drill contains the information: P nom = 900 W. Let’s calculate how many kW is given value power:

P nom = 900 (W)/1000 = 0.9 (kW).

The name of the unit of power measurement (kW) is familiar to everyone who has at least once taken meter readings to an electricity supply organization. For people far from electricity, some clarification should be made. The consumer pays for the electricity consumed, which is measured in kilowatt × hour, as can be seen in the photo below.

One kilowatt hour is the energy consumed from electrical network when a load of 1 kW is connected to it for an hour. For example, a powerful 500 W incandescent lamp, when turned on for one hour, consumes electrical energy in a volume of 500 W × hour.

We choose two things in the store that should be used “in tandem,” for example, an iron and a socket, and suddenly we encounter a problem - the “electrical parameters” on the label are indicated in different units.

How to choose instruments and devices that suit each other? How to convert amps to watts?

Related but different

It must be said right away that a direct conversion of units cannot be done, since they represent different quantities.

Watt - indicates power, i.e. the rate at which energy is consumed.

Ampere is a unit of force that indicates the speed at which current flows through a specific section.

To ensure trouble-free operation of electrical systems, you can calculate the ratio of amperes and watts at a certain voltage in the electrical network. The latter is measured in volts and can be:

• fixed;
• permanent;
• variables.

Taking this into account, a comparison of indicators is made.

"Fixed" translation

Knowing, in addition to the values ​​of power and strength, also the voltage indicator, you can convert amperes to watts using the following formula:

In this case, P is the power in watts, I is the current in amperes, U is the voltage in volts.

Online calculator

In order to constantly be “in the know,” you can create an “ampere-watt” table for yourself with the most frequently encountered parameters (1A, 6A, 9A, etc.).

Such a “relationship graph” will be reliable for networks with fixed and constant voltage.

"Variable Nuances"

To calculate at AC voltage The formula includes one more value - power factor (PF). Now it looks like this:

An accessible tool such as the online amperes to watts calculator will help make the process of converting units of measurement faster and easier. Do not forget that if you need to enter in the column a fractional number, this is done through a period, and not through a comma.

Thus, to the question “1 watt - how many amperes?”, using a calculator you can give the answer - 0.0045. But it will only be valid for a standard voltage of 220V.

Using the calculators and tables available on the Internet, you can not agonize over formulas, but can easily compare different units of measurement.

This will help you select circuit breakers for different loads and not worry about your household appliances and the condition of the electrical wiring.

Ampere - watt table:

First of all, let's deal with Soviet resistors.

No matter what you do, Soviet electronics you can't escape. Therefore, a little theory will not harm you.

At first glance, we must estimate what maximum power the resistor can dissipate. From top to bottom, below in the photo, resistors by power: 2 Watt, 1 Watt, 0.5 Watt, 0.25 Watt, 0.125 Watt. On resistors with a power of 1 and 2 Watts they write MLT-1 and MLT-2, respectively.

MLT is a type of the most common Soviet resistors, from abbreviated names M metal film, L lacquered, T heat resistant. For other resistors, the power can be estimated based on their dimensions. The larger the resistor, the more power it can dissipate into the surrounding space.

Units of measurement in MLTs - Ohms - are designated as R or E. Kilo-ohms - with the letter “K”, Mega-ohms with the letter “M”. Everything is simple here. For example, 33E (33 Ohms); 33R (33 Ohm); 47K (47 kOhm); 510K (510 kOhm); 1.0M (1 MOhm). There is also a trick that letters can precede numbers, for example, K47 means that the resistance is 470 Ohms, M56 - 560 Kilohms. And sometimes, in order not to bother with commas, they stupidly push a letter there, for example. 4K3 = 4.3 Kilohm, 1M2 – 1.2 Megaohm.

Let's look at our hero. Let's look immediately at the designation. 1K0 or in the words “one and zero”. This means that its resistance should be 1.0 Kilohm.

Let's see if this is really true?

Well, yes, everything agrees with a small error.

Color coding of resistors

To determine the resistance value of a color-coded resistor, you first need to rotate it so that its silver or gold stripes are on the right and a group of other strips are on the left. If you cannot find a silver or gold strip, then you need to rotate the resistor so that the group of strips is on the left side.

The color of the strip is a coded number:
Black – 0
Brown – 1
Red – 2
Orange – 3
Yellow – 4
Green – 5
Blue – 6
Purple – 7
Gray – 8
White – 9

The third bar has a different meaning: it indicates the number of zeros that should be added to the previous digital value obtained.

Stripe Color – Number of Zeros
Black – No zeros -
Brown – 1 – 0
Red – 2 – 00
Orange – 3 – 000
Yellow – 4 – 0000
Green – 5 – 00000
Blue – 6 – 000000
Purple – 7 – 0000000
Gray – 8 – 00000000
White – 9 – 000000000

It should be remembered that color coding is quite consistent and logical, e.g. green color means either the value 5 (for the first two stripes) or 5 zeros (for the third strip).

The sequence of colors itself coincides with the sequence of colors in the rainbow (from red to purple colors) (!!!)

If a resistor has a group of four stripes instead of three, then the first three stripes are numbers, and the fourth strip indicates the number of zeros. The third digital strip makes it possible to indicate the resistance of the resistor with higher accuracy.

Let's look at a resistor unknown to us.

Basically, there are three, four, five and even six stripes on a resistor. The first strip is closest to the resistor terminal and is made wider than all other strips, but sometimes this rule is not followed. In order not to sift through reference books on the color marking of resistors, you can download many different programs on the Internet for determining the resistor value.

You can also find a very good online calculator .

Resistor marking calculator

I really liked the program. Even a preschooler can understand this program. Let's use it to determine the value of our resistor. We drive in the strips of the resistor we are interested in and the program will give us its value.

And at the bottom left in the frame we see the resistor value: 1kOhm -+5%. Convenient isn't it?

Now let's measure the resistance using a multimeter: 971 ohms. 5% of 1000 ohms is 50 ohms. This means that the resistor value must be in the range from 950 Ohms to 1050 Ohms, otherwise it can be considered unsuitable. As we can see, the value of 971 Ohms fits perfectly into the range from 950 to 1050 Ohms. Consequently, we have correctly determined the value of the resistor, and it can be safely used for our purposes.

Let's practice and determine the value of another resistor.

All OK;-).

Marking of SMD resistors

Digital marking of resistors

Let's look at the markings of resistors. Resistors of size 0402 (size values) are not marked. The rest are marked with three or four numbers, since they are a little larger and you can still put numbers or some kind of marking on them. Resistors with a tolerance of up to 10% are marked with three digits, where the first two digits indicate the value of this resistor, and the last third digit is 10 to the power of this last digit. Let's look at this resistor:

The resistance of the resistor shown in the photo is 22x10 2 = 2200 Ohms or 2.2 K.

Let's check if this is true? We take this tiny SMD component between the probes and measure the resistance.

Resistance 2.18 kOhm. A small error does not count.

SMD resistors with a tolerance of 1% and size 0805 and larger are marked with four numbers. For example, a resistor with the number 4422. This is calculated as 442x10 2 = 44200 Ohm = 44.2 kOhm.

There are also SMD resistors with almost zero resistance (there is still a very, very small resistance) or simply so-called jumpers. They look more aesthetically pleasing than any wires.

Coding resistors is the most common practice these days. Sometimes you come across resistors whose markings look very strange. Don't be alarmed, this is a simple code marking that is used by some manufacturers of electronic components. It might look something like this:

or even like this:

How to determine the resistance value of such resistors? For this purpose, there is a table with which you can easily determine the value of any resistor with a code marking. So, the first two digits contain the secret value of the resistor, and the letter is the multiplier.

Here is the actual table:

Letters: S=10 -2 ; R=10 -1 ; A=1; B= 10; C=10 2 ; D=10 3 ; E=10 4 ; F=10 5

This means that the resistance of this resistor is

we will have 140x10 4 = 1.4 MegaOhm.

And the resistance of this resistor

we will have 102x10 2 = 10.2 KiloOhm.

In the Resistor 2.2 program you can also easily find code and digital markings of resistors.

Choosing the BOURNS branding

Place the marker on “3 characters”. And we type our code marking. For example, the same resistor marked 15E. Below, on the left in the frame, we see the resistance value of this resistor: 1.4 Megaohms.