Use slashes sparingly, and use them to express genuine alternatives, such as:

Beware of suggesting a false alternative, as in this example:

The use of the slash implies two modes of operation, one called normal and one called general; in fact, the writer is describing only one mode of operation, called by alternative names, normal and general. Clearer expression would have been:

Excessive use of slashes makes a text seem hurried and slapdash. It is usually wiser to use or, not a slash:

Beware, too, of implying or when you mean and, plus, against, or versus:

Preferably, do NOT use a slash to express a ratio or a range:

14.2 Signalling ‘per’

Use a slash to show when a unit for a physical quantity is divided by a unit for another physical quantity:

14.3 Signalling fractions in prose text

If you wish to include simple fractions in prose text, preferably spell them out in full:

But if the fraction is complex, and would seem clumsy if written out (for example, sixteen two-hundred and fortieths), write it in full-size characters, with a slash separating the numerator from the denominator: