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I've simulated the diode in LTspice and the result indicates two current peaks in the diode, the higher one(5.4A) only lasts 60us in the very beginning and the lower one(1.8A) lasts 3ms.

My question is whether should I choose the diode which can withstand the higher current peak(5.4A)? The reason for this question is because the higher one only last 60us and I'm not sure whether the diode can ignore such a short current peak.enter image description here

Ross
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  • Check the diode's datasheet, it might say. – user253751 Sep 24 '18 at 04:10
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    This is really a duplicate of [this one](https://electronics.stackexchange.com/questions/21598/overclocking-an-avr): sure you can go out of spec if you don't care how the part will behave. If you want the diode to behave like a diode, it's recommended to stay within the spec. – Dmitry Grigoryev Sep 24 '18 at 11:23
  • Could you explain the purpose of the diode in your circuit? Could you explain the purpose of your circuit and what you ultimately want to accomplish? A circuit diagram would help too. Without knowing such thing, it's difficult to answer your question (or, it's easy to give you a wrong answer). – Nick Alexeev Sep 24 '18 at 14:30

1 Answers1

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Almost all devices will have a continuous specification, and a pulse specification which is higher.

However, the ratio of these depends on the detail design of the device, and the length of time the manufacturer, and you, consider 'pulse'. Get the datasheet, for that specific device, and read it carefully.

For instance, the 1N540x series rectifier diode specifies 3A continuous (with certain mounting and ambient conditions), and 200A for a duration of 8.3mS (1/2 a cycle of 60Hz, to deal with capacitor reservoir inrush).

Good news. When you do a parametric sort of a supplier's online parts catalogue, the current figure for diodes is usually the lower continuous rating.

Neil_UK
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  • Thank you for your answer. I read the diode datasheet and found that the peak forward surge current is 30A for 10ms, so it fit my design. – Ross Sep 24 '18 at 04:54
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    @RossLee It's usually a good plan when asking questions like this to link to the datasheet of the specific device you're using. – Neil_UK Sep 24 '18 at 05:30