Commenting in a spice file is quite straightforward. Start a line with an * and the entire line is a comment. The first line is comment by default. An example is as follows:
* This is how your write a comment in a spice file
That much is clear from the following references:
http://newton.ex.ac.uk/teaching/cdhw/Electronics2/userguide/sec2.html
http://www.ecircuitcenter.com/Basics.htm
http://home.olemiss.edu/~atef/engr360/tutorial/qgspice.html
However, I have been unsuccessful so far in finding a reference, which explains how to add comments at the end of a line. The third link mentions the use of ; but it is unclear about it. For example:
R1 3 4 1K ; Is this a comment?
In LTspice (and in spice in general) is it a frowned upon practice to add comments at the end of the line?
Best Answer
SPICE is not a well-standardized netlist description language. Every SPICE can introduce it's own syntax, special symbols, circuit elements, etc. Historically, only full-line comments were used ('*' in the first column), but there's no reason some particular SPICE might not allow ';' to introduce an end-of-line comment.
From the LTSpice Help file, under the heading "General Structure and Conventions':
So LTSpice does, indeed, allow end-of-line comments starting with a semicolon.