Voltage formula Unit of measurement. Determination of electrical stress

Before considering the concept of electric current voltage, briefly remark the concept of the current in general. In very general concept - This is an ordered, directional motion of charged particles (electrons) produced under the influence electric field. You can also not forget about the strength of the current - one of the main values \u200b\u200bof electricity. When moving charges electric field Makes a certain job.

He connected many of these sources in the series to create the first chemical battery. It became known as the battery and gave people the opportunity to generate electricity using chemical reactions. The voltage measurement unit, volt, as well as the term "voltage" itself is invoked in such a way as to mark the contribution of volts to the search for electrochemical and electrical phenomena. Thanks to him, we know that we have a reliable electrochemical source of energy.

When we talk about researchers who worked on the creation of devices for electricity generation, we should not forget the Dutch physicist Wang de Graph. During the generation of electricity, the same principle of the separation of charges is used when we wipe the amber and fur. We can say that two outstanding American scientists Thomas Edison and Nikola Tesla were fathers of modern electric generators. Tesla worked at Edison, but both researchers did not agree with how to produce electricity and depart on separate roads.

Principle of voltage operation

Than greater charge must be moved in 1 second to electrical chainThe greater work is performed by an electric field. Therefore, its work is completely dependent on. However, in addition to the strength of the current, there is another value that affects the work. This will be the tension that will be discussed.

The voltage is the ratio of the current operation on the segment of the chain to the size of the charge passing through this section of the electrical circuit. In other words, this is the work (energy) consumed when moving one positive charge From a point with a small potential to a point with great potential. The voltage is defined as a difference in potentials or electromotive power.

After the work of these two scientists, a patent war was held, and humanity received benefits. Today there are billions of devices using the mechanism used in these reversible machines. We find them under the hood of our car, the regulator power window or blender among other devices. On the other hand, it was Tesla that found ways to generate an AC and the principle of its transformation. These discoveries are used by such devices as electrical transformers, electrical lineswhich carry electricity over long distances and others.

The unit of measurement of electric current is Joule (J), the electrical charge is measured in the cabins (CL). Thus, the voltage measurement unit is 1 J / CL. This unit was called Volt (B), in honor of Alessandro Giuseppe Antonio Anastasio Volta (1745-1827) - Italian scientist physics and chemist, one of the founders of electricity doctrine.

There are many such devices and includes many household electronics, which are often used by us in everyday life, such as fans, chillers, air conditioners, vacuum cleaners and many other devices that we cannot describe here because of the purpose of this article.

Finally, scientists have discovered other electrical generators using different principles, including using nuclear fission energy. Some of these other generators are intended for use as sources of energy during long-lasting visits.

How this unit is working in practice

If you explain simply, for the uninitiated, the volt will be considered a measure of "pressure" or the impact that causes the electric current to move around the chain or wire. At the same time, the amp will be its measure "volume". To clearly explain the work of Volta and Ampere, as an example, you can use the principle of "water in the hose". Here, the voltage in volts will be similar to the pressure of water, and the force in amperes is the volume of water. If water enters the hose without a tip, then a large amount of water passes through it (), the pressure occurs a small (volt). When we press the tip of the hose with a finger, the volume of water passing on it decreases, but the water pressure increases and the jet splashes much further.

If we do not consider some of the generators created for scientific research, we can say that the most powerful sources of electricity on Earth are still atmospheric processes. This means that tens of thousands of Van de Grafa generators in nature simultaneously generate currents in tens of kilograms in the form of lightning strikes. However, we cannot start comparing artificial generators with earth with electric storms that occur on the sister of the Earth, Venus, and we do not even try to withstand them with storms on big planets, such as Jupiter and Saturn.

Comparing this example with electricity, we see that the current of the current is the number of electrons passing through the wire, and the voltage shows us, with what force these electrons are pushing. It follows from this that with the same voltage at the wire, conducting larger electrical current must be larger diameter.

Voltage characteristics

Voltage can be characterized by its size and shape of the wave. Precision electronic devices are used to supply electricity and maintaining a constant voltage level. They operate using electrical components and are also known as voltage regulators.

Many industries of science and technology, including chemistry and fundamental physics, applied electrical engineering and electrochemistry, as well as medicine, widely use voltage measurements. It is difficult to imagine a discipline that does not use voltage measurement to control various processes. These measurements are manufactured using various types of sensors that are measuring transducers of various voltage properties. Some exceptions from this, or rather, were possibly some creative areas of human activity, such as architecture, music or art.

For voltage in electrical network Be sure to be needed any current source. When the electrical circuit is in an open state, the voltage exists only on the terminals of the source itself. When the current source is turned on in the electrical circuit, voltage occurs in separate areas. Simultaneously in the circuit there is a strength of the current. We observe the relationship: without voltage - there is no current strength.

Currently, musicians and artists also use electronic devices that rely on tension. For example, artists and designers can use electronic plates with stylus. The voltage is measured in these tablets when the stylus moves to the surface of the tablet. It is converted to digital signals and sent to the processing computer. Musicians and composers often work with electronic musical instruments. The voltage is measured in key sensors to determine the keystroke intensity.

To measure the voltage, a special electrical measuring device is used, which is called a voltmeter. In its appearance, it is practically similar to, and differs only by the scale. On the scale of the ammeter - the letter "A", at the Voltmeter - the letter "V". When performing measurements, the ammeter is turned on in a circuit sequentially, and a voltmeter-parallel.

The meat temperature is measured by an electronic thermometer on the left, measuring the voltage on the resistance temperature sensor. This is achieved by supplying a small electric current through this sensor. On the other hand, the meter on the right determines the temperature, measuring the voltage created by the thermocouple, without supplying any current from an external power source.

Voltage units may vary wide limits: from the share of microvolt when searching for biological processes, hundreds of volts in consumer electronic devices and industrial equipment and tens of millions of volts in potent accelerators. The voltage measurement allows us to control and control some functions of some internal organs of the human body. For example, to display the brain function, we write down the "electroencephalogram" to understand how the heart works, we write the electrocardiogram or heart echocardiogram.

Hello everyone, in touch with you again Vladimir Vasilyev. New Year's celebrations are approaching the end, and it is necessary to prepare for workers' weekdays, with what our dear friends and congratulations! Heh, just do not be upset and depressed, you need to think positively.

With the help of various industrial sensors, we can successfully and safely monitor various processes occurring during chemical production. Some of these processes occur with extreme pressure and temperature, and for this reason, safety is an important task. Measuring voltage, we can also control processes on nuclear power plants that occur during nuclear reactions. Engineers also support bridges and structures in good condition, measuring tension, and can also prevent or reduce the destructive effects of the earthquake.

So here in these new Year holidays I somehow reflected on the audience of my blog: "Who is he? Who is the visitor of my blog, that every day comes to read my posts? ". Maybe this wanted specs went out of curiosity to read what I am drunk here? Or maybe this is some kind of doctor of radio engineering scouts to see how to discharge the multivibrator scheme?

Like a voltmeter, the pulse oximeter measures the signal voltage enhanced by the photodiode. However, compared with the voltmeter, this device shows the saturation rate of hemoglobin oxygen, 97% in this example, and not the voltage measured in volts. Bright idea to connect different values Voltages to the logical levels of signals that led to the creation of modern digital technologies. For example, low voltage information Low logic, and high voltage - high logic.

It can be said that all modern computer and electrical devices somehow measure the voltage, and then convert their logic input states using specific algorithms to obtain output signals in the required format.

You know, all this is unlikely, because for a watched specialist, all this has already passed the stage and most likely everything is not so interesting and they themselves with a mustache. They can only be interesting from idle curiosity, it is certainly very nice to me and I am waiting for everyone with open arms.

So I came to the conclusion that the main contingent of my blog and most of the amateurs of amateur sites is newcomers and lovers who grow on the Internet in search of useful information. So what Lesheh, I have it so little? Will be in the soon time more so do not miss!

Voltage Measurement Devices

In addition, accurate voltage measurements are the basis for many modern safety standards. Following these standards in accordance with the prescriptions, you will ensure your safety when using the device. Throughout history, when we learned a lot about the world around us, our tension measurement methods were evolved from primitive organoleptic methods. An example of such methods is the work of the Russian scientist Petrova, who removed the epithelium from the fingers to increase its sensitivity to electric Toku..

I remember myself when I was looking for some simple scheme for a simple scheme to start with something, but something constantly did not fit, something seemed awake. I lacked Azov, such that it was possible on the principle of a simple to begin to begin to understand the topic of interest to me.

By the way, the first book that I really helped, from reading which an understanding is really beginning to come - it was the book "The Art of Chapera" P. Horowitsa, W. Hill. I wrote about her in, there and the book can be downloaded. So, if you are new, then you must download it and let it become your desk book.

These methods allowed it to develop simple detectors and voltage indicators, and then modern devices with various electrodynamics and electrical properties of materials and substances. It is interesting to note that in the past, when modern measuring instruments, such as multimeters, were not available for the general public, fans of radio electronics could say that the battery lamp for 4, 5 volts works from the one who loses the charge they did it simply, licking the electrodes .

Electrochemical processes arising when they did it, caused a slight burning sensation and gave a battery some taste. Some people also tried to determine if there were 9 volts good batteries to use, but it took a little courage, because the feeling was very unpleasant.

What is voltage and current?

By the way, what is the electric current and voltage? I think no one actually does not know, because to know this at least to see. Who can see the current running on the wires?

Yes no one, humanity has not yet reached such technologies to observe the movement electrical charges. All that we see in textbooks and scientific works is some abstraction created as a result of numerous observations.

Consider an example of a simple indicator or voltage tester - a conventional incandescent lamp with a voltage of no less network voltage. It should be noted that voltmeters that are voltage measurement devices can differ significantly from each other, and the most significant difference is the type of voltage measured. The properties of the voltage measured are very important during the measurement process. It can be a function of time and be of a different type, for example, a straight, harmonic, anonymous, impulse, etc. Signals.

The most common stress types are most common. Instant voltage, peak peak voltage, voltage, also known as the average voltage, the average quadratic root voltage. We can control the time voltage on the oscilloscope screen and determine the voltage at the moment of time, exploring the track. The average value of the voltage is the arithmetic average of all its instantaneous values \u200b\u200bfor the period during which the measurement takes place.

Well, I can talk about it a lot ... So let's try to figure out what electric current and voltage is. I will not write definitions, definitions do not give the very understanding of the essence. If I wonder, take any textbook on physics.

Since we do not see it with electric current and all the processes in the explorer, then try to create an analogy.

The medium-term average voltage is calculated as arithmetic absolute instantaneous values \u200b\u200bfor voltage samples for a specified period of time. The difference between the minimum and maximum voltage value is known as signal oscillation.

Currently, the voltage is often measured using multifunctional digital devices, such as oscilloscopes. This screen can display several important characteristics of the signal, and not just the voltage signal form, which include the frequency of measured periodic signals. It should be noted that the frequency limit is a very important feature of any measuring device voltage.

And traditionally, the electric current current in the conductor is compared with water running through the pipes. In our analogy, water is an electric current. Water runs through the pipes at a certain speed, the speed is the current force measured in amperes. Well pipes this is a conductor.

Well, the electric current we imagined, but what is the tension? Now fromse.

Voltage measurement with oscilloscope

We can illustrate the previous discussion using numerous voltage measurement experiments. Here is the configuration of the experiment 1. The oscilloscope of the oscilloscope and the multimeter are connected parallel to the resistor. When carrying out this experiment, we must keep in mind that the oscilloscope bandwidth is higher than the multimeter bandwidth.

First we will try the experiment. Test 1. Attach a sinusoidal signal with a frequency of 60 Hz and a 4 volt amplitude from the generator to the load resistor. The track will be displayed on the oscilloscope screen as in the following figure. We will use experiment 2 as the same settings that were used for the experiment.

Water in the pipe, in the absence of any forces (weight of gravity, pressure) there will be a bit, it will rest like any other alone poured on the floor. So this force is or more accurate to say the energy in our plumbing analogy and it is therefore voltage.

But what happens to the water running from the tank located high above the ground? Water rushes a rapid flow from the reservoir to the surface of the Earth, persecuted by the forces. And the higher from the Earth there is a tank of topics with a larger speed flows water from the hose. Do you understand what I'm talking about?

The higher the tank, the more power (read the voltage) affecting water. And the greater the water flow rate (read the current strength). Now it becomes clear and colorful picture begins in the head.

The concept of potential, potential difference

With the concept of voltage of electric current, the concept of "potential", or "potential difference" is closely connected. Well, turn again to our plumbing analogy.

Our reservoir is located on an elevation that allows water to smoothly flush along the pipe down. Since the tank with water at the height, the potential of this point will be higher or more positive than what is at the ground level. See what happens?

We had two points having different potentials, or rather different amounts of potential.

It turns out that the electric current can run through the wire, the potentials should not be equal. The current runs from the point with great potential to the point with less potential.

Remember such an expression that the current runs from the plus to minus. So this is all the same. Plus it is a more positive potential and minus more negative.

By the way, do you want a question on the backfill? What happens to the current if the values \u200b\u200bof the potentials will periodically change places?

Then we will observe how the electric current changes its direction to the opposite one every time the potentials will change. It will work out already alternating current. But we will not consider it until we are, in order to have a clear understanding of the processes formed in the head.

Voltage measurement

To measure the voltage, the voltmeter device is used, although multimeters are now the most popular. Multimeter is such a combined device having a lot of things. I wrote about him and told how to use it.

Voltmeter This is just the device that measures the potential difference between the two points. The voltage (potential difference) at any point of the circuit is usually measured relative to zero or earth or mass or minus batteries. It does not matter the main thing this should be a point having the smallest potential in the whole scheme.

So to measure the voltage direct current Between two points, we do the following. Black (minus) The probe voltmeter sticks into the point where we presumably we can observe a point with less potential (zero). Red probe (positive) stick to the point whose potential is interesting to us.

And the measurement result will be the numerical value of the potential difference, or in other words voltage.

Measurement of current

In contrast to voltage, which is measured at two points, the current value is measured at one point. Since the strength of the current (or they say simply) in our analogy there is a water flow rate, then this speed must be measured only at one point.

We need to cut the plumbing and insert a certain counter into the gap that will count liters and minutes. Something like this.

Similarly, if we return to the real world of our electrical model, then get the same. To measure the magnitude of the electric current, we need to connect a simple device to break the electrical circuit - an ammeter. The ammeter is also part of the multimeter. You can also read in.

Multimeter probes need to be rearranged into the current measurement mode. Then they snack our conductor, and connect the scraps of the wire to the multimeter and voila - the current value will be shown on the multimeter screen.

Well, expensive friends, I think that we did not lose time in a gift. After reviewing our plumbing models in the head began to make a puzzle, the beginning to form an understanding.

Well, let's try to check it on the Ohma law.

I - current measured in amperes (a);

U-voltage measured in volts (B);

R resistance measured in Omah (OM)

I said to us that the electric current is directly proportional to the voltage and inversely proportional to the resistance.

I didn't say about resistance today, but I think that you understood. Electric current resistance is conductor material. In our plumbing system, rusty pipes are driven by rust and other things.

Thus, the Ohm law works in all its glory that for plumbing systemWhat for electrical. Maybe I go to the plumbing, there is a lot of similar.

The higher the reservoir with water, the faster the pipes will be the water. But if the pipes are rushing, then the speed will be less. The more water resistance, the slower it will be leak. If the zoom, then water can get up at all.

Well, for electricity. The value of the current depends is directly proportional to the voltage value (potential difference), and inversely proportionally depends on the resistance.

The higher the voltage, the greater the current value, but the more resistance the smaller the current value. The voltage can be very large, but the current may not happen due to the cliff. And the break is like that if instead of a metal conductor, we connected the conductor from the air, and the air has simply gigantic resistance. Here is the current and stop.

Had dear friends, that's time to call, it seems that everyone wanted to say in this article I said. If you need any questions ask in the comments. Further will be more, I plan to write a series of tutorials, so do not miss…

I wish you good luck, success and to new meetings!

With N / P Vladimir Vasilyev.

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