Technology card, are technologies "tapped"???

By Arcturion, in Twilight Imperium

Have a question regarding the Technology Strategy card . A player of ours ,while he had the technology strategy card ,used a technology he already had existing to research his free technology. He then wanted to then use both of those technology cards with the second ability, to then research another technology . We are used to playing in games where once you use a card it is considered tapped or exhausted. Is this the case in the example and the player cannot research the second technology since he "used" the first one already? Or in fact is it that technologies used as perquisites for research are never "tapped"/ exhausted when a player uses as such as above?

Edited by Arcturion
further explanation

You never 'exhaust' a tech unless something specifically says to do so (as far as I can recall, this happens only on a few particular tech cards instructing you to do so in order to use their ability).

Meeting prerequisites consists exclusively of having that tech (even on the off chance that it has been exhausted by an ability earlier in the round). The only complication comes from planet cards with tech specialties -- you can exhaust a planet with a tech specialty to ignore one corresponding prerequisite. I am guessing that your error here comes from mis-understanding the mechanics associated with this. You do not exhaust techs and planets to meet prerequisites. You possess techs to meet prerequisites or exhaust planets to ignore (not technically 'meet') them.

that's exactly what happened. We knew the planets got exhausted with the tech specialty, and made the leap maybe techs were as well. ty very much!!