L2N3

Due to market price fluctuations, if you need to purchase or consult the price. You can contact us or emial to us:   sales@allicdata.com

Thyristors - TRIACs

The term ‘Triac’ refers to the device employed in AC applications and is a shortened version of the words ‘Triode-analog AC switch’. A TRIAC is a type of thyristor, which is a semiconductor device employed for switching, protecting, and controlling electrical power applications. It is a three-terminal semiconductor device consisting of an anode, a gate, and a cathode. Depending on the current direction and the potentials applied to the three terminals, the TRIAC exhibits two different modes of operation; OFF-state mode and ON-state mode.

L2N3 application field and working principle

The TRIAC has a wide range of applications due to its unique operation and power control capabilities. One of the important applications is ‘Phase-angle-control’ and ‘Zero-crossing’ switching circuits. It is widely used in commercial, industrial and residential AC applications as a digital-analogue switch such as light dimming, lamp control, fan speed control, or motor speed control. The TRIAC has a number of advantages over other thyristor circuits such as; it can be triggered from either direction of current, it can be used in both AC and DC applications, and it can be operated in off-state mode to keep the current flowing for a longer duration or to create a delayed action.

The working principle of the TRIAC can be understood in terms of the following three states, which define its operation:

• OFF-state mode: - In this state the anode-cathode voltage is reversed biased and no current flows between these two terminals. The gate terminal should be shorted to the cathode and a normally open (NO) switch should be closed in order to run the TRIAC.
• ON-state mode: - This state occurs when the anode-cathode voltage is applied forward biased and a current flows through the terminals. This can be achieved by opening the NO switch and applying a positive bias (-NL) to the gate terminal.
• Triac triggering: - The TRIAC is triggered when the gate current (IG) reaches a certain threshold value, this is referred to as ‘Holding Current’. This current can either be increased or decreased to control the time taken for the TRIAC to reach its ON-state.

The application of TRIAC’s, their advantages and applications, along with the various states and their significance regarding, TRIAC operation, make them a versatile device in AC power control system applications.

The specific data is subject to PDF, and the above content is for reference