Re: Another Spice Trap?

From: Mike Engelhardt (nospam_at_spam.org)
Date: 11/22/04 

Date: Mon, 22 Nov 2004 04:26:14 GMT

Paul,

>> The usual SPICE convention is for the direction
>> of positive current flow to be from the 1st node
>> to the 2nd node of a capacitor. In LTspice, for
>> the cap symbol, that's from node "A" to node "B"
>> which is downward if the symbol is placed without
>> rotating it.
>
> C'mon, Mike; fix the problem and make every LT user
> happy. It ain't no big deal!

I(C1) has a sign convention that LTspice follows.
You can even refer to that current in behavioral
expressions -- something missing in most SPICE's,
e.g., PSpice.

If you get confused with the direction of current
in a cap, just add a phasing dot to the symbol,
something you can do yourself with the graphical
symbol editor.

But the program should not ship with phasing dots
on such symbols.

--Mike