Most people, one way or another confronted with electronics, the basic device of field-effect and bipolar transistors should be known. At least from the name “field effect transistor”, it is obvious that it is controlled by the field, the electric field of the gate, while the bipolar transistor is controlled by the base current.

Current and field are a cardinal difference. For bipolar transistors, the collector current is controlled by changing the control current of the base, while to control the drain current of the field effect transistor, it is enough to change the voltage applied between the gate and the source, and no control current is needed anymore. The advantage of field-effect transistors, in comparison with bipolar ones, is obvious: field-effect transistors have a high input resistance in direct current, and even control at a high frequency does not lead to significant ...

When choosing an air heater, or just a heater, the first question is what type of heater to choose. After answering the first question, the necessary power of the device of the selected type is approximately calculated so that it can heat the room of the corresponding area. Approximately take 1 kW per 10 square meters. And finally make the long-awaited purchase.

But if in appearance all these steps seem unpretentious and simple, then as soon as it comes down to business, a lot of nuances immediately pop up to the surface. What type of device to choose? What are the pros and cons of devices of one type or another? Which is best suited to current conditions? We will try to honestly answer these questions in this article. Namely, we compare the two most popular today, and at the same time completely different, such as air heaters - heating elements and ceramic ...

For street lighting in settlements, energy-efficient luminaires with sealed reflectors are now used. On highways and major freeways, reflex lighting is often used with a reflective surface inside the luminaire, which allows the creation of powerful streams of directional light. For secondary roads, reflex and diffused lighting are equally suitable.

The most powerful lanterns, with power from 250 to 400 W, are installed on freeways, the less powerful ones are used to illuminate secondary roads - 70 - 250 W, and for pedestrian sidewalks and park areas, scattered lighting with lamp power from 40 to 125 W is sufficient. Street lighting fixtures in settlements have shades of various shapes: for parks these are balls and cylinders, for wide streets - directional floodlights ...

When the cable design is known, its resistivity is calculated from the resistivity, thickness and length of the metal of the current-carrying core. The specific reactance and length determine the total reactance of the cable. Often, for calculation, it is enough to take a directory with tables and calculate the types of resistances (active and reactive) from the cable brand with certain technical characteristics. Knowing the two legs of a right-angled triangle, the hypotenuse is calculated - the value of the complex resistance.

A cable is created to transmit a nominal current. Multiplying its numerical value by the complex resistance, we find out the magnitude of the voltage drop. Both legs are calculated similarly. Next, simple trigonometric calculations are performed.Also, special tables, graphs and diagrams summarized in technical manuals are used to calculate voltage losses. ...

Power surges are one of the most common problems faced by residents of apartments or private houses during the operation of electrical appliances. By the concept of voltage surges we mean, as a rule, short-term or impulse changes in the voltage value, both in the direction of increase and decrease.

Depending on the cause, the voltage drops can have a different frequency, amplitude and total duration. In any case, this phenomenon is abnormal and the question arises as to how dangerous it is for household electrical appliances and home wiring and how to eliminate the possible consequences of this phenomenon. In this article, we will consider in detail the question of why voltage surges occur and how to protect oneself from them. First of all, it should be noted that each household appliance is designed for normal operation, provided that it is powered ...

Electronic locks are increasingly becoming part of the life of a modern person. The number of varieties of electronic locks is very large, and mechanical ones are gradually replaced by them. Recently, biometric locks have appeared on the horizon, about which something is already known, and they will be discussed in this article.

What is biometrics in general? It all starts with the fact that for authenticating a person, the owner of an apartment, house or safe, you can use individual information, the source of which is DNA: a picture of a fingerprint or iris, an image of the retina or veins on the front of the eye - these are individual keys, which can be used as such for opening and closing a biometric lock, because there are no people with the same DNA in the world. The electronics of the biometric lock will analyze the fingerprint pattern, compare it with its base ...

What would you say if you knew that the bulbs in your apartment are capable of something more than just turn on and off at the touch of a button? But what if the color of the glow of the lamps could be independently selected and adjusted? What about controlling the light directly from your smartphone? All this is possible with Philips Hue lamps. These LED lamps will shine in exactly the color that you choose, and with the brightness that you adjust by simply using the application for iPhone or Android. Interesting, isn't it?

The Philips Hue kit includes 3 LED lamps and a wireless controller for them with its own power supply. The lamp bases are the most common E27, the maximum brightness of each lamp of 600 lumens approximately corresponds to a 50-watt incandescent lamp, and the consumption of each Philips Hue lamp is 5 times less than that of an incandescent lamp of a similar brightness ...

A situation is quite common when the established number of outlets in a room in an apartment is not enough to simultaneously include all the necessary household appliances in the network. In this regard, one or several electrical appliances have to be connected to the network one at a time, which is not very convenient and ordinary household chores are delayed in time. How to solve this problem?

If the wiring is quite old and is in unsatisfactory technical condition, then it is necessary to replace it, mounting a new wiring already with the number of outlets necessary for convenient operation. But this option, as a rule, is combined with the overhaul of an apartment or a private house, since with a complete replacement of the wiring it will be necessary to violate the integrity of the finish coating of the walls and ceiling throughout the house ...