Is the thyristor a current type or a voltage type device? How is it distinguished? What is the principle?

Thyristors are current-mode devices, while IGBT is voltage-mode devices. Thyristors generally refer to thyristors.

Silicon controlled rectifier is divided into unidirectional silicon controlled rectifier and bidirectional silicon controlled rectifier. TRIAC is also called triac. The bidirectional thyristor is structurally equivalent to two unidirectional thyristors connected in reverse, and has the function of bidirectional conduction.

Its switching state is determined by the control electrode G. Adding a positive pulse (or negative pulse) to the control electrode G can make it turn on in the forward direction (or reverse direction). The advantage of this device is that the control circuit is simple and there is no reverse withstand voltage problem, which is especially suitable for AC contactless switches.

Current control type is a circuit with current as the main feedback control, which is different from voltage control type and also has hybrid type. Current-controlled devices, such as common NPN, PNP triode, SCR, etc., have relatively large current when voltage control is applied due to their small internal resistance (generally, low-power devices are above 100uA, and high-power devices can reach more than 20mA), and the amplification can be realized by adding the base driving current.

Extended data:

Precautions:

When selecting the rated current of thyristor intelligent module, we should not only consider the average current through the components, but also pay attention to the size of the conduction angle, heat dissipation and ventilation conditions during normal work. It should also be noted that the temperature of the casing does not exceed the allowable value under the corresponding current.

Before using the thyristor intelligent module, use a multimeter to check whether the thyristor intelligent module is in good condition. When short circuit or open circuit is found, it should be replaced immediately.

Thyristor intelligent module with current above 5A shall be equipped with radiator, and the specified cooling conditions shall be guaranteed. In order to ensure good contact between the radiator and the core of thyristor intelligent module, a thin layer of silicone oil or silicone grease should be coated between them to facilitate good heat dissipation.

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