What is a triak?

TIAC is an electrical component that has two wires used to connect AC current (AC) and the third line used to start the device. Unlike some other devices, such as transistors and diodes, the triac can perform current in both directions between two conductive wires. The starting part of the device called its gateway turns on or off the device to different stages. The use of the gate in conjunction with the AC phase can be set triac to allow only a part of the AC signal to pass through it and is often used in devices such as dimmers and electric motor control, the word triak, created by a trio with AC, was originally a trade name for its silicone -based version. Since its original edition, however, the word has become a general name for all such devices. In a suitable way, the device is referred to as bidirectional or bilateral triodic thyristors.Not quite accurate, because the device is basically a configuration of two thyristors.

Thyristor is a specialized semiconductor device usually made of four layers of silicon connecting together. Four individual layers of silicon are treated so that they have alternating electric charges of positive negative-positive negative or PNPN. Each end of the layers serves as a connector for access to the thyristor. The positive end is the anode of the device and the negative end of its cathode. The gate connection is also created with positive layers of sandwich between two negatively charged layers.

Under static conditions, alternating layers of resistant to resist the hub allow to flow through thyristor. However, there is a limit of voltage that the device can withstand. If the appliance applied to the device exceeds this limit, the device succumbs to the effect called an avalanche and starts electric current.

For the purpose of controlling the thyristor, a negative voltage is applied to its gate. This changes the charge into a positive layer to a more negative slope that can cause an avalanche. Changing the voltage at the gate may vary by an avalanche point of the thyristor, which allows the device to perform electrical current only at a predetermined voltage.

AC signals are continuously alternating from full positive voltage towards zero voltage, then towards the full negative voltage, back towards zero voltage, and then back to a full positive voltage. This means that the alternating signal is constantly changing the voltage level. As a result, a change in the tyristor gate voltage can be the percentage of AC voltage that can pass through the device, change and drive.

However,

thyristors can only perform an electrical current in one direction, which will block half of the alternating current voltage in the same way as the diode. In order to use a full alternating voltage, a triac from two thyristors is designed. By connecting the anode of one thyristorWith the cathode of the other at one end and the remaining cathode and the anode at the other end, both devices can perform a single alternating voltage in both directions. Both gates, also interconnected, allow one control signal at the gate to control the alternating signal passing through the triac. In this way, the triac can provide any required part of the AC voltage to the device, such as the engine, and by changing the gate voltage changes the engine speed.