So I'm going through this book and reading about diodes. There are these elaborate equations to calculate the ripple and avg/max current in the diode. In one example, the max current is calculated to be 2.5A. The author concluded that the diode has to be spec'ed for at least 2.5A.

So I simulated circuit, and while LTSpice shows the max current to be only 1.6A, the initial charging current goes all the way to 8.2A. So if I'm using a 2.5A diode, I am out of luck and my rectifier diode will get destroyed by the surge.

Here is the circuit:

https://www.dropbox.com/s/gppvgw7d2ywru9g/Full%20Wave%20Bridge%20Rectifier.asc?dl=0However I looked up the 1N4001 datasheet and found 2 paramters : Average rectified output current (1A), and peak forward surge current (30A). The first parameter is a little mysterious. Average with respect to what? (given that the diode is on only for a short amount of time). So is it average while the diode is on? That would correspond to the calculated average from the book which is half the max which would be 1.25A (the book derive that iDmax = 2 * iDavg) and we would be out of spec with the 1N4001 (1.25A > 1A).

The 8.2A would be within the surge max 30A parameter and all is good, but that renders the calculated max of 2.5A useless. Is there a rule of thumb to calculate the max surge current out of the max repetitive charging current?