Thyristors - TRIACs

A Triac, also known as a symmetrical Triode Thyristor (TRIode-forAlternatingCurrent) or STT, is a type of thyristor that has unique features. The Q4004F312 is a type of TRIAC, which provides bidirectional control of current and voltage. It is basically a two-channel triac that can switch and control both halves of the AC cycle through its two independent gate pins. The Q4004F312 is designed for high-voltage, high-current switching applications such as motor control, lamp dimming, and relay control.

Triac Working Principle

A triac is a three-terminal, bidirectional switch made up of two pnpn silicon structures. Internally, it looks like two anti-parallel thyristors connected together. Each thyristor can be triggered at their corresponding gate terminals to activate the device. When one thyristor is turned on, the other thyristor will turn off. By connecting the two gate terminals, both thyristors can be turned on simultaneously, allowing the device to conduct current in both directions.

The Q4004F312 uses a special technique to control the current and voltage throughout the triac. During each half of the AC cycle, the current is controlled by varying the gate current. By varying the gate current, the voltage across the device can be increased or decreased depending on the requirements of the application. This is known as phase control, which enables the Q4004F312 to be used in a variety of motor control and dimming applications.

Q4004F312 Application Field

The Q4004F312 is typically used in motor control, lamp dimming, and relay control applications. It is well-suited for applications that require bidirectional current switching and high levels of current and voltage control. The device is particularly well-suited for small motor control applications such as appliance, domestic and consumer products, lighting control, and digital temperature control.

In addition, the Q4004F312 is suitable for applications where digital control is not required but reliable AC switching is needed. It has built-in temperature and overload protection and can be used in thermowell protected applications in both capacitive and resistive loads.

The device delivers high performance and improved reliability in switching and controlling a wide range of AC loads. It also provides electrical isolation between the control circuit and the load, which allows it to be used in systems with high-voltage and low-voltage control circuits.

Conclusion

The Q4004F312 is a versatile three-terminal, bidirectional TRIAC that provides bidirectional current and voltage control. It is primarily used in motor control, lamp dimming, and relay control applications. The device delivers excellent performance and increased reliability, making it well-suited for a wide range of applications. Additionally, the device offers built-in temperature and overload protection and can be used in thermowell protected systems.