Repetition of hyphen in shared prefixes [duplicate]

Possible Duplicate:
Can a hyphen be used without anything on the right side?

I'm trying to discuss types of semiconductor, there is P-type and N-type. Assuming my hyphenation is correct, should it be 'p- and n-type' or just 'p and n-type'?

It would be P- and N-type; writing P and N-type leaves it open to the interpretation that you are talking about a single type called "P and N" rather than two types, named "P" and "N".

I would write "P-type and N-type". Describing the technology accurately and unambiguously is more important than annoying grade school English teachers and dictionary pedants.

People may also search your text for "P-type"