some fun with "spice models" .... 1N4004 vs 1N4007

[Kevin Zheng]

> So this is intended as "food for thought".  Can you explain the
> differences between these models?  Do you know what the real difference
> between a 1N4004 diode and a 1N4007 diode is?

An interesting enough question to pull me out from the weeds :)

I work on compact models, but for MEMS, and so my semiconductor physics are
a bit rusty. Still, I think I have a pretty complete answer and so will be
posting it in a couple of days.

In the meantime, happy 2023!