Hi all,
this is driving me mad.
I'm thinking of a component that I'm sure exists but can't look it up as I can't remember what it is called!!!
Remember the old remote release leads for cameras when you pushed the plunger at one end and a pin came out the other releasing the shutter? It's something like that but with out the lead. Just a unit that is retracted when LOW and extended when HIGH (no smut thanks! 
)
Something like a 2 position servo but without the rotation?
Have I made this up or am I just old and forgetful?
Many thanks
