Date：2025-01-17 Categories：Product knowledge Hits：333 From：Guangdong Youfeng Microelectronics Co., Ltd
In order to correctly select thyristor components, it is necessary to understand their main parameters. Generally, the average or limit values of the parameters are provided in the product catalog, and the measured data of the components are marked on the product certificate.
(1) Off state repetitive peak voltage UDRM
Under the conditions of open circuit of the control pole and forward blocking of the thyristor, the forward peak voltage can be repeatedly applied at both ends of the thyristor, which is 100V lower than the forward transition voltage.
(2) Reverse repetitive peak voltage URRM
When the control pole is open circuited, the reverse peak voltage that can be repeatedly applied to the thyristor component is specified to be 100V lower than the reverse breakdown voltage.
Usually, the smaller value between UDRM and UDRM is labeled as the rated voltage on the device model. Due to the fact that transient overvoltage can also damage thyristors, when selecting, the rated voltage should be 2-3 times the normal peak operating voltage as a safety factor.
(3) Rated on state average current (rated forward average current) IT
The average value of the power frequency sine half wave current (within one cycle) that thyristor components can continuously pass through under the conditions of ambient temperature not exceeding 40 degrees and standard heat dissipation, i.e. full conduction, is called the rated on state average current IT, abbreviated as rated current.
(4) Maintain current IH
The minimum current required to maintain the continuity of the component under the specified ambient temperature and control pole open circuit conditions is called the holding current IH. Generally, it ranges from tens of milliamps to over one hundred milliamps, and its value is inversely proportional to the temperature of the component. It maintains a current of about 25 degrees Celsius at 120 degrees Celsius. When the forward current of the thyristor is less than this current, the thyristor will automatically turn off.
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