A direct current is a current that almost (since there is nothing perfect in the world) changes in time, neither in magnitude nor in direction. Historically, the first direct current sources were exclusively chemical. At first they were represented only by galvanic cells, and later batteries appeared.

Galvanic cells and batteries have a strictly defined polarity, and the direction of the current in them does not change spontaneously, therefore chemical current sources are fundamentally direct current sources. The AA AA battery is a prime example of a modern galvanic cell. A cylindrical alkaline battery (which they like to call alkaline, while the word alkaline is translated as alkaline) contains a solution of potassium hydroxide as an electrolyte inside. At the positive pole of the battery is manganese dioxide, and at the negative - zinc in the form of a powder ...

The word "buzzer" comes from the German "summen" - buzz. In essence, this is a sound-emitting device traditionally used as a signaling device. To date, buzzers are electromechanical and piezoelectric. Both that and others find application in different devices.

Historically, the first appeared electromechanical buzzer, which is an electromechanical relay with normally closed contacts through which the coil of this relay is connected to a current source. The principle of operation of the buzzer is simply impossible. When a current flows in the buzzer's working circuit, the relay coil is excited, which means that the magnetic flux in its core increases, under the influence of which the contacts through which the coil itself has just been fed open immediately. When the contacts are opened, the relay winding stops receiving power, the magnetic flux in the core disappears, which means that the movable contact that just closed the circuit is released ...

The electric car is the most modern vehicle, and motorists are increasingly transplanting them in many countries of the world. About a million people around the world are actively using electric cars, because unlike traditional cars that run on combustible fuel, an electric car is more economical to operate and generally more practical.

Nevertheless, when changing a vehicle to an electric one, the driver will inevitably have questions regarding maintenance, repair, the cost of batteries, etc. Despite all these questions, it turns out that electric cars ultimately still have a number of advantages over ordinary cars. And in this article we will talk specifically about batteries for electric cars. So, electric cars are cars that use electric energy stored in a battery for their drive ...

No electrical work in the building is complete without wall chipping. To lay hidden wiring, a wall (groove) is first made in the wall, then cables are laid into it, after which the wall with the wiring is sealed with a solution.

Traditionally, in the process of strobing, a special power tool called a stroborez (groove cutter) is first used, then a perforator with a special nozzle in the form of a scapula is used to completely clean the furrow. Finally, the wiring is laid in the gate. In general, channels in concrete or brick walls are made not only for wiring and other cables, but also for water and sewer pipes, ventilation ducts and all that sort of thing.In addition to wall chipping, electrical work includes: drilling holes for socket boxes, for soldering boxes, drilling holes for plastic mounting dowels etc....

To begin with, in a regular LED strip, regardless of whether it is single-color or RGB, all the LEDs of the tape are powered and lit at the same time, since they all receive power in parallel from one source, a driver that works according to its own algorithm, implemented directly inside the driver, and it simply supplies power to the entire tape at once, in fact - to all LEDs connected in parallel to it.

Address LED strip, in contrast to the usual, contains the so-called address LEDs. This means that although each LED receives power in parallel from a common source, each LED turns on according to an individual command, and that means that each LED can get its own unique shade, one of 255³ = 16581375 possible. Each LED in the tape has its own unique address, at which the driver accesses it using a three-bit command ...

Proper installation provides more than 50% of the ability of a fire-resistant cable line (OKL) to resist fires). We'll figure out what “competent installation” means. The concept of “fire-resistant cable line” appeared in 2013. In essence, OKL is a ready-made, laboratory-tested set of equipment for installation: a special cable and mesh for its suspension, metal trays, junction boxes, couplers, dowels, anchors.

OKL necessarily has a certificate of conformity 123-ФЗ "Technical regulation on fire safety requirements" and GOST R 53316-2009 (or GOST 31565-2012), which specifies the installation procedure: all possible components and their combinations are considered, for each OKL configuration option are indicated uptime and fire resistance limits. If you follow the instructions from the certificate, then it is impossible to make a mistake when installing OKL. However, in practice, many installers work according to the usual pattern ...

For a substance to be able to conduct an electric current, it must have charged particles capable of moving freely through its entire volume under the action of an applied electric field. In metal conductors, for example, such charged particles are free electrons, and in electrolytes, positively and negatively charged ions.

Dielectrics do not conduct a constant electric current at all, since although there are charged particles in their structure, they are connected to each other and cannot move freely, forming a current. But even dielectrics pass alternating current, this is called a bias current, for example, a capacitor in an alternating current circuit at a certain frequency will conduct current as if it were a conductor. As for ordinary water (river, tap, especially sea water, etc.), dissolved mineral substances are always present in it ...

To expand the functionality of multimeters, oscilloscopes, and other electrical measuring instruments, current sensors in the form of ticks are used - current clamps. To take measurements with clamps, they are closed into the girth of the conductor with current, and thus, without breaking the circuit and without the need to cut any shunt into the conductor, they measure.

It is simple and convenient. The device displays the measurement result on its scale in the form of voltage or current proportional to the measured current value.The advantage of the method lies in the fact that the device may not have a sufficiently wide input range, while the sensor - clamps are quite able to freely accept the conductor even with a very high current. The conductor with the measured current not only remains intact, but is always galvanically isolated from the circuits of the measuring device. The device itself may have an input circuit with a very high impedance ...