Ask about the selection of bidirectional thyristor

sky999

Ask about the selection of bidirectional thyristor [Copy link]

 

In a 220V 5A circuit, is there any difference between using a 6A bidirectional thyristor and a 16A one? Do I need to leave a margin?

chunyang

This depends on the load characteristics, and the maximum current of the load needs to be analyzed, including transient current and duration.

ddllxxrr

There is a difference. 6A can only carry less than 6A current. If it is larger, it will not work. 16A can only carry 16A current at most. The price is also expensive. The original poster's product is not enough for me. I considered buying a 40A product a few days ago.

sky999

chunyang posted on 2021-1-11 17:34 This depends on the load characteristics. It is necessary to analyze the maximum current of the load, including transient current and duration.

That makes sense. If the maximum is 10A and the average is 5A, should I choose one greater than 10A, or just greater than 5A?

sky999

ddllxxrr posted on 2021-1-11 20:58 There is a natural difference. 6A can only carry less than 6A of current. If it is larger, it will not work. The maximum current of 16A is 16A, and the price is also expensive. The original poster's is not enough for me, I...

Will the leakage current increase if the current of the thyristor is larger?

qwqwqw2088

The current should have a safety margin of 1.5 to 2 times

sky999

qwqwqw2088 posted on 2021-1-12 09:07 The current should have a safety margin of 1.5 to 2 times

OK, thanks. Is the current of the thyristor proportional to the leakage current?

maychang

sky999 posted on 2021-1-12 10:03 OK, thank you. Is the current of the thyristor proportional to the leakage current?

"Is the current of the thyristor proportional to the leakage current?"

Each model of thyristor is different, so you should read the instructions for that model of thyristor carefully.

ddllxxrr

sky999 posted on 2021-1-11 23:26 The greater the current of the thyristor, will the leakage current be greater?

No, the thresholds are the same.

chunyang

sky999 posted on 2021-1-11 23:26 It makes sense. If the maximum is 10A and the average is 5A, should we choose one greater than 10A, or one greater than 5A?

If the maximum current is 10A, you must choose a device with at least 10A. If the 10A current lasts for a long time, you should even choose a larger one to leave enough margin to ensure the reliability of the device. If it is less than 5A at ordinary times, but 10A for a very short time, you may be able to use a 5A device, but you still need to perform transient analysis to ensure reliability.

chunyang

sky999 posted on 2021-1-11 23:26 The greater the current of the thyristor, will the leakage current be greater?

Generally speaking, this is the case, at least for the same series. But it may not be the case for different series. The leakage current of some high-current thyristors can be lower than that of low-current thyristors of different series. The specific information must be based on the device manual.

A similar situation exists for the trigger current.

sky999

chunyang posted on 2021-1-12 23:31 Generally speaking, this is the case, at least for the same series. But it may not be the case for different series. The leakage current of some high-current thyristors can be lower than that of different series...

How do you read the leakage current of a thyristor in the manual? Which item?

sky999

maychang published on 2021-1-12 10:39 "Is the current of the thyristor proportional to the leakage current?" Each model of thyristor is different, and the manual of the thyristor should be read carefully.

Is the leakage current of the thyristor written in the manual? Which item is it?

chunyang

sky999 posted on 2021-1-13 12:53 How do you read the leakage current of a thyristor in the manual? Which item?

IDRM and IRRM usually have the same value.

maychang

sky999 posted on 2021-1-13 12:54 Is the leakage current of the thyristor written in the manual? Which item is it?

For example, this item in the BTA136 manual:

sky999

OK, thank you two upstairs