The charge Q, as the amount of electricity, is measured in coulomb (C), the electric capacity of the capacitors C is in farads, microfarads (microfarads), but the battery capacity is measured for some reason not in farads, but in ampere-hours (milliampere-hours). What would that mean? One ampere is a pendant in one second, we know from the course of physics that if an electric charge equal to 1 pendant passes through a conductor in 1 second, then a current of 1 ampere flows through the conductor.

And then what is ampere hour? An ampere-hour (Ah) is considered to be the battery capacity at which, according to a given current of 1 ampere, the battery is discharged 1 hour before the minimum allowable voltage. For example, for a lithium-ion battery of size 18650, with a capacity of 3400 mAh, this means that the battery at a current of 340 mA can give its charge in 10 hours, and a car battery with a capacity of 55 Ah is discharged from about 12.8 to 10.8 voltsin 2 hours at a discharge current of 27.5 A ...

Summer residents who ennoble their plot, have to deal with the need to lay wires to connect lamps in the yard, electrify workshops, garages and sheds. The line can be laid underground, but then you need to dig trenches, use expensive armored cables, PND-corrugation and so on for laying. As a result, the volume and cost of the work are quite large. Another option is to lay the line through the air. In this article we will tell you how to lay a wire through the air in the country or in a country house.

To conduct light and install sockets in utility rooms in a summer cottage or in the courtyard of a private house, you need to decide how to lay the cable. We will make a reservation that any building can be in the role of an outbuilding - a barn, workshop, garage and bathhouse. There are three options: laying along the fence and walls, underground cable entry into the building, and laying the cable through the air ...

With the simultaneous inclusion of several power receivers in the same network, these receivers can easily be considered simply as elements of a single circuit, each of which has its own resistance. In some cases, this approach turns out to be quite acceptable: incandescent lamps, electric heaters, etc. - can be perceived as resistors. That is, the devices can be replaced by their resistance, and it is easy to calculate the parameters of the circuit.

The method of connecting the power receivers can be one of the following: serial, parallel or mixed type of connection. When several receivers (resistors) are connected in a serial circuit, that is, the second terminal of the first is connected to the first terminal of the second, the second terminal of the second is connected to the first terminal of the third, the second terminal of the third and the first terminal of the fourth, etc., when this circuit is connected. ..

By their physical nature, all substances react differently to the flow of electric current through them. Some bodies pass it well and they are referred to as conductors, while others are very bad. These are dielectrics. The properties of substances to counteract the flow of current are estimated by numerical expression - the value of electrical resistance.

The principle of its definition was proposed by Georg Om. The unit of measure for this characteristic is named after him. The relationship between the electrical resistance of a substance, the voltage applied to it, and the flowing electric current is called Ohm's law. Based on the dependence of the three most important characteristics of electricity shown in the picture, the resistance value is determined.To do this, you must have: an energy source, for example, a battery or accumulator, measuring instruments for current and voltage. The voltage source is connected through an ammeter ...

The speed of rotation of an induction motor is usually understood as the angular frequency of rotation of its rotor, which is given on the nameplate (on the nameplate of the motor) as the number of revolutions per minute. A three-phase motor can be powered from a single-phase network, for this it is enough to add a capacitor parallel to one or two of its windings, depending on the mains voltage, but the motor design will not change from this.

So, if the rotor under load makes 2760 revolutions per minute, then the angular frequency of this engine will be 2760 * 2pi / 60 radians per second, that is, 289 rad / s, which is not convenient for perception, therefore they simply write “2760 rev / min. " As applied to an induction motor, these are revolutions taking into account slip s. The synchronous speed of this engine (excluding slip) will be equal to 3000 rpm, since when supplying stator windings with mains current...

Most often, people are interested in electronics in order to be able to repair a device. Only a small part of lovers are engaged in self-development. Although theoretical knowledge provides a general understanding of how the components work, it’s much more important to know how to test them for repairs. We will tell you how to find a malfunction in an electronic circuit with your own hands, eyes and a simple tool.

Before carrying out repairs it is important to determine what the problem is - this process is called diagnostics. So, we can distinguish two stages of testing electronic devices. It does not always happen that the device is completely “dead”, you need to check if the device does not turn on at all, or turns on and off immediately, or some specific buttons or functions do not work. For example, when repairing LCD monitors, there is such a problem as a backlight failure. At the same time, the monitor may or may not turn on completely then its indicator blinks ...

The question of whether to install an RCD on the lighting circuit has recently been relevant. Meanwhile, there are no strict regulations regarding the installation of RCDs on lighting lines. Let's see what the RCD can give in this case, and how things will be without it. After which each reader will be able to conclude for himself whether to put the RCD on the lighting or not.

First, recall the principle of operation of the RCD. The differential current transformer inside the RCD allows you to detect the excess of the differential current. If such an excess occurs, the protected electrical circuit will open. RCD is included in the gap of the protected circuit - in the gap of the neutral and linear conductors. After the RCD is put into operation, the contact inside it is closed by a solenoid, held in this state, and the device freely passes a current through the supply circuit ...

The word "levitation" comes from the English "levitate" - to soar, to rise into the air. That is, levitation is the overcoming by the object of gravity when it soars and does not touch the support, without repelling from the air, without using jet propulsion. From the point of view of physics, levitation is a stable position of an object in a gravitational field, when gravity is compensated and there is a restoring force that provides the object with stability in space.

In particular, magnetic levitation is the technology of lifting an object using a magnetic field, when magnetic action on an object is used to compensate for the acceleration of gravity or any other acceleration.It is about magnetic levitation that will be discussed in this article. Magnetic retention of an object in a state of stable equilibrium can be realized in several ways. Each of the methods has its own characteristics, and each can be presented ...

Speaking of a value that varies according to a sinusoidal (harmonic) law, it is possible to determine its average value over half the period. Since the current in the network in our overwhelming majority of cases is sinusoidal, for this current its average value (for half the period) can also be easily found, it is enough to resort to the integration operation, setting the limits from 0 to T / 2.

Substituting Pi = 3.14, we find the average, over half the period, value of the sinusoidal current depending on its amplitude. Similarly, the average value of the sinusoidal EMF or sinusoidal voltage is found. However, the average value is not as widely used in practice as the effective value of a sinusoidal current or voltage. The effective value of a value sinusoidally varying in time is the root mean square value, in other words, its effective value ...

LED is a rather gentle semiconductor device. If the current through its P-N junction becomes critically larger than the nominal, then overheating will begin and thermal destruction of the crystal will not take long. Therefore, before checking the LED for serviceability, be prepared to be very careful not to accidentally spoil the workpiece.

Small round LEDs are designed for an operating voltage in the range of 2 to 4 volts, namely: red, yellow and green - up to 2.2 volts, and white and blue - up to 3.6 volts. The operating rated current of a small round LED usually does not exceed 10 - 20 milliamps, keep this in mind. So, to check the LED, you first need to decide what you will use to check. If there is no multimeter at handthen the first thing you can take a power source with a known voltage in the range from 5 to 12 volts, but do not rush to connect ...

Leakage current as a physical phenomenon You have probably heard the expression "leakage current" or "leakage current to earth", but can anyone explain what it is? What causes a leakage current, why is it dangerous, how to eliminate it? We will try to get an answer to these questions.

Firstly, for a leak to occur, a current needs a closed electrical circuit, like any conduction current. And practically any conductive object can become a load here: a person’s body, bathtub, pipe, part of the electrical installation case, etc. And if the leakage current turns out to be excessively high, then there may be a danger to human health. That is why it is necessary to have an idea of ​​this phenomenon. Schematically, the figure shows the path that the leakage current has laid for itself through the human body. Why did the current go through the body in this example? Because the resistance between the housing and the live parts of the installation ...

Common-mode choke is the most important component of the input filter of any switching power supply. The fact is that during the operation of a pulse converter of any topology, when switching field-effect transistors, common-mode interference occurs, which propagate in the conductors and along the tracks of the printed circuit boards.

These interferences are harmful high-frequency impulse currents that flow simultaneously along the plus and minus wires, and in the same direction.If these interference eventually gets into the AC power network, then they can not only lower the quality of functioning of the devices connected to the network in the neighborhood, but even disable them, especially the signal circuits of digital units. For this reason, today all household appliances, which in principle can become sources of common-mode interference, are equipped with common-mode chokes ...