A triac is a type of thyristor. He, like the Trinistor, has three conclusions, but the triac pn junctions are not three, but five. Two stable states are also characteristic of a triac: “open” and “closed”, while the conductivity of the triac can be controlled in two directions, despite the fact that it has only one control electrode.

Due to its versatility, it is the triac most often plays the role of a key in AC circuits for controlling various kinds of devices (for example, the engine of a grinder or a washing machine). Take a look at the drawing. There are five transitions, which in their arrangement are similar to two counter-parallel connected trinistors. If you attach plus to the electrode MT2, and minus to MT1, then it is activated(ready to go) transition sequence bottom-up n-p-n-p, and when you change the polarity at our disposal will fall...

Many beginner hams find it difficult to determine the type of power supply, but it's not so difficult. The main methods of voltage conversion are the use of one of two circuitry options: transformer and transformerless power sources.

In turn, transformers differ in the type of circuit: network, with a transformer operating at a frequency of 50 Hz and a pulse, with a transformer operating at high frequencies (tens of thousands of Hz). Pulse circuits of power supplies can increase the overall efficiency of the final product, by avoiding static losses on linear stabilizers and other elements. If there is a need for power from a 220 V household power supply, the simplest devices can be turned on from power supplies using ballast elements to lower the voltage. A widely known example of such a power source ...

LEDs replace these types of light sources, such as fluorescent lamps and incandescent lamps. Almost every house already has LED lamps, they consume much less than two of their predecessors (up to 10 times less than incandescent lamps and 2 to 5 times less than CFLs or energy-saving fluorescent lamps). In situations where you need a long light source, or you need to organize illumination of complex shape, an LED strip is used.

Led tape is ideal for a number of situations, its main advantage over individual LEDs and LED arrays are power sources. They are easier to find on sale in almost any electrical goods store, unlike drivers for high-power LEDs, moreover, the selection of a power supply is carried out only by power consumption, because the vast majority of LED strips ...

Does studying microcontrollers seem complicated and incomprehensible? Before the appearance of Arudino, it was really not easy and required a certain set of programmers and other equipment. This is a kind of electronic constructor. The initial objective of the project is to allow people to easily learn how to program electronic devices, while devoting minimal time to the electronic part.

The assembly of the most complicated circuits and the connection of the boards can be carried out without a soldering iron, and with the help of jumpers with detachable connections “father” and “mother”. In this way, both attachments and expansion cards can be connected, which in the lexicon of arduinists are simply called “Shields”. The base and most popular board is considered Arduino Uno. This fee resembles a credit card. Most shields that are on sale are ideally suited to it. On the board for connecting external devices ...

AVR is the name of the popular Atmel family of microcontrollers. In addition to ABP, microcontrollers (hereinafter MK) and other architectures, for example, ARM and i8051, are produced under this brand. There are three types of microcontrollers AVR 8-bit, AVR 32-bit and AVR xMega.

For more than a decade, the most popular is the 8-bit MK family. Many hams began to study microcontrollers from him. Almost all of them learned the world of programmable controllers by doing their simple crafts, such as LED flashing lights, thermometers, clocks, as well as simple automation, such as controlling lighting and heating appliances. Microcontrollers AVR 8-bit, in turn, are divided into two popular families: Attiny - the name shows that the youngest (tiny - young, young, younger), mainly have 8 pins or more. The amount of their memory and functionality is usually more modest ...

At the very beginning of the topic, regarding the selection of a quenching capacitor, we consider a circuit consisting of a resistor and a capacitor connected in series to a network. Let us consider from a practical point of view the question of selecting a quenching capacitor for inclusion in the AC network of a load designed for a voltage lower than the standard mains voltage.

Suppose we have a 100 W incandescent lamp designed for a voltage of 36 volts, and for some incredible reason we need to power it from a 220 volt household network. Having such a capacitor, we gain hope to get a normal glow of the lamp, we hope that at least it will not burn out. This approach, when we proceed from the effective value of the current, is acceptable for active loads, such as a lamp or heater. But what if the load is non-linear and connected through a diode bridge? Let's say you need to charge lead acid ...

Often, when designing a powerful device on power transistors, or resorting to the use of a powerful rectifier in the circuit, we are faced with a situation when it is necessary to dissipate a lot of thermal power, measured in units, and sometimes tens of watts.

For example, Fairchild Semiconductor's FGA25N120ANTD IGBT transistor, if installed correctly, is theoretically capable of delivering about 300 watts of thermal power through its chassis at a chassis temperature of 25 ° C! And if the temperature of its case is 100 ° C, then the transistor will be able to give 120 watts, which is also quite a lot. But in order for the transistor case to be able to give this heat in principle, it is necessary to provide it with the proper working conditions so that it does not burn out ahead of time. All power switches are issued in such cases which can be easily installed on an external heat sink - a radiator ...

In the article "How to control a chandelier in two wires", various schemes were considered that allow switching several groups of lamps. The operation algorithm for all circuits is the same: with a short click of the switch, the first group lights up, with the second second, with the third click both groups at once. To turn off the chandelier, switch the switch, as usual, to the open position. All the circuits considered at different times were developed by ham radio.

In Chinese-made chandeliers, such devices are already installed, and in addition to them there are some additional lighting and even sometimes sound effects. My colleague at work was engaged in the repair of one of these devices: until you are busy repairing production equipment, you can work hard for yourself. And the defect of the mentioned device was like this - no matter how you click the switch, nothing turns on. Still managed to repair the circuit ...