I've occasionally come across this symbol which appears to be a capacitor with a wire through the middle - but I've never seen it on anything where I could get a look at what component it corresponds with physically, and I've never seen it defined in a list of component symbols.
Have a look at the first schematic here and look at the earth rail - you'll see what I mean. It has always puzzled me - can anyone shed any light?
If I'm looking at the correct symbol, that's a feed through capacitor.
They are common on RF devices where they allow wires to enter a shielded enclosure.
Looking at the picture from the link you gave here they are:
Those are known as "feed-through" capacitors.
They provide a way to get a wire into or out of a shielded enclosure - the capacitor gives some filtering to prevent unwanted signals from travelling along the wire.
You can see them where components/wires pass through the top and bottom sides of the small enclosure in the bottom view of the radio.
It looks like a feed through capacitor. The chassis is grounded and the wire passes from one side to the other to form a connection.
I think this is "Adjustable Capacitor" or "Variable capacitor". From the schematic it seem to control things like bandwidth. In addition is is in parallel with other components so I this cannot be a wire through capacitor.
Check bottom of page: http://www.learnabout-electronics.org/ac_theory/capacitors01.php
Yes, feed-through capacitor, also known as a coaxial capacitor.
"RF" means radio freqruency. Example, when you're in your car trying to find a radio station, you rotate the dial to the radio station you would like to listen to. In order to listen to that radio station, you have to turn dial to match the same frequency of the radio station.
With that being said, the capacitors with the line are variable capacitors. The dial on a radio is a variable capacitor. That is why dashed lines from the symbol are pointing to are dials. The capacactance can be changed to obtain a certian frequency.
Look up Variable Capacitors.
