L2004F81

Thyristors - TRIACs: L2004F81 Application Field and Working Principle

The L2004F81 is a four-quadrant silicon control rectifier (SCR) or thyristor, first developed by Siemens AG in 1984, for use in pulse width modulation and/or switched-mode power supply (SMPS) applications. It is primarily used in power control applications and its application field can range from controlling the speed of an electric motor to the precise control over a resistive furnace.

In terms of its functionality and working principle, an SCR or the L2004F81 is an electrically triggered solid-state switch. In a general sense, the device can be thought of as the combination of two p-n junctions with a control-gate between them. In the case of the thyristor, it consists of four interconnected impedances which form three p-n junctions. When a small current flows through the gate, it triggers the internal structure of the L2004F81 and causes it to open or fire. Once it has fired, the thyristor remains in the “on” state and no further action from the gate is necessary. This makes the thyristor the ideal choice for use in high-current applications.

The L2004F81 is a unidirectional two-terminal device with two primary terminals, an anode and a cathode. The anode is the positive (+) terminal whereas the cathode is the negative (-) terminal. When the anode is positively biased relative to the cathode, a flow of majority carriers or electrons is allowed through the thyristor. The L2004F81 is a four-layer device and, unlike the common SCR, it can be forced to turn on by applying a positive gate (G) voltage at the gate terminal.

The L2004F81 uses a patented current focal point method to control the on/off conduction state of the device. This is a “Pulsed Voltage” control method, where a positive gate pulse of a certain width is repeated during the course of operation and creates a transient voltage peak within the device. This high voltage peak helps the thyristor to remain in the on state even when the gate current flows into the device reaches a negative peak value. This means that the thyristors can be operated at higher frequencies than usual.

In terms of its physical characteristics, the L2004F81 is designed to dissipate heat efficiently. The device features a heatsink, which is connected to the anode terminal and helps to spread the heat evenly over the entire body of the device. This effectively helps the device to maintain its temperature and higher performance. The device can also be mounted on a circuit board and is typically used in industrial applications.

Finally, the L2004F81 is also designed for easy integration into digital power supply systems. It can operate as a standalone device or as part of a sophisticated power control system. Further, the device can be operated in both single-phase and three-phase power supplies. Due to its high switching speed, the device is capable of making fast response decisions and executing them in the shortest possible time. This makes the L2004F81 ideal for applications where fast and precise power control is necessary.

In conclusion, the L2004F81 is an SCR or thyristor for use in pulse width modulation and/or switched-mode power supply (SMPS) applications. The device uses a patented current focal point method to control the on/off conduction state of the device and features a heatsink which helps to dissipate heat efficiently. It is designed to be used in both single-phase and three-phase power supplies and can be used in a variety of industrial applications, where fast and precise power control is required.