I am working on an electronics for scientists and engineers book that uses the ~ to indicate "poorly approximates". I have searched for a rule that governs how to space this symbol for the following expression. ~1 mA < |I| < ~10 mA
The logical operator symbol for ~ means "not" which is not how this is being used so I am unsure if this is to be treated as a sign of comparison like a normal double tilde approximation symbol is.
I don't think that this single tilde is being used as a comparison sign since, in the second instance in this example, it follows a "less than" sign. This tilde means “approximately” much in the same way the tilde means “not” in logic. (It is a qualifier here, not a sign of comparison.) I would braille it unspaced from the number to which it applies.