bidirectional diode thyristor:A Comprehensive Discussion of Operating Principles, Characteristics and Application

The bidirectional diode thyristor is a semiconductor device with a four-layer PNPN structure with bidirectional conductivity. It can conduct electricity not only in the forward conduction state but also in the reverse conduction state. This device is usually made of semiconductor material silicon or germanium and has two ports, namely P terminal and N terminal. When current flows from the P terminal to the N terminal, it blocks the present, and conversely, it allows the current to pass. Bidirectional diode thyristors can replace the role of diodes and are more widely used.

The working principle of the bidirectional diode thyristor is based on the unique properties of semiconductor materials. It consists of two anti-parallel PN junctions. This structure makes it bidirectionally conductive and can conduct current in both forward and reverse directions. When a forward voltage is applied between the anode and cathode of the diac thyristor and a trigger current is applied to the control electrode, the thyristor will conduct in the forward direction.It is worth noting that once the thyristor is turned on, the control voltage loses the control effect. Regardless of whether there is a control voltage or not, and irrespective of the polarity of the control voltage, the thyristor will always be conducting. To turn off the thyristor, reduce the anode voltage to a critical value or apply a reverse voltage. The volt-ampere characteristic curve of the triac is symmetrical, so adding a positive or negative trigger pulse to the control electrode of the triac can trigger the tube to conduct. Therefore, bidirectional thyristors are commonly used in AC control switching applications.



Features and advantages of bidirectional diode thyristors:

Bidirectional conductivity: Diac thyristors can conduct current in both forward and reverse directions, similar to diodes, but are more widely used.

Efficient: The disc thyristor is highly efficient because it can send current to the right place quickly, which makes it particularly useful when efficient circuits are required.

Reliable: Bidirectional diode thyristors have high reliability and can operate normally over a wide temperature range.

Fast response: The response speed of the bidirectional diode thyristor is breakneck and can achieve rapid control of the current in a short time.

Small size: The size of the bidirectional diode thyristor is smaller than that of ordinary diodes, which can save circuit board space and make the circuit design more compact.

Protection function: The bidirectional diode thyristor has overvoltage and overcurrent protection functions, which can effectively protect the circuit from damage.

Temperature stability: Bidirectional diode thyristors have good temperature stability and can maintain stable performance at different temperatures.


Diacs have a wide range of applications

High-frequency inverter: A bidirectional diode thyristor can be used in a high-frequency inverter to convert DC power into AC power to achieve power conversion.

Switching power supply: Bidirectional diode thyristor can be used in changing the power supply to control the on and off of the power supply to realize the switching function of the power supply.

Power active filter: A bidirectional diode thyristor can be used in a power active filter to suppress and compensate harmonics in the power system and improve the stability of the power system.

Motor control: Bidirectional diode thyristors can be used to realize motor speed regulation, braking and other functions.


Things to note when using bidirectional diode thyristors include:

Connect the pins correctly: A triac has two control poles (G) and two main bars (A and K). When connecting, you need to ensure that the control pole is connected correctly, that is, to the control voltage source. At the same time, pay attention to the correctness of the primary pole connection to ensure that the current flows in the correct direction.

Please choose the appropriate trigger current and trigger voltage: The trigger current and trigger voltage of the triac are vital parameters for making it conductive. When selecting a bidirectional thyristor, the appropriate trigger current and trigger voltage should be chosen according to actual application requirements. Too high or too low trigger current or voltage may cause the triac to fail to work correctly.

Please pay attention to the limit voltage: When using a bidirectional thyristor, consider its limit voltage parameters. If the limit voltage is exceeded, the triac may be damaged. Therefore, during use, ensure the applied voltage does not exceed its limit voltage.

Ensure thermal stability: Since trials consume much power in the on state, attention must be paid to their thermal stability. If the heat dissipation is poor, the temperature of the thyristor may be too high, affecting its performance or even damaging it. Therefore, good heat dissipation conditions must be ensured during use.

Avoid overcurrent and overvoltage: When using bidirectional thyristors, it is necessary to avoid overcurrent and overvoltage. Overcurrent and overvoltage can damage trials, so protection needs to be added to the circuit to prevent this.

Reliability and installation connections: When using bidirectional thyristors, you must pay attention to their reliability and installation connections. Make sure the pin connection is reliable to avoid failures caused by poor pin contact or loose contact. At the same time, you must pay attention to its polarity and direction during installation to prevent problems caused by incorrect connections.

In short, when using bidirectional diode thyristors, these precautions must be correctly understood and followed to ensure the bidirectional thyristor can work properly in the circuit.