15th July 2008, 20:36
Several days ago, feeling the need to build a variable capacitor of 150pF, I set to work with a sheet of thin aluminium, pile of washers, nuts & bolts, brass rod & acrylic & set off. Never been up to much at theory, I guessed the vane sizes, but made more than I needed. Original assembly had four fixed & five moving. Bit too low. Added one more of each & got almost exactly 150pF. Bit of messing about with acrylic end plates & fixings, but completed it this afternoon. I will now build a two valve short waver to go with it!