The Challenge: Make a radio from a saucepan
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Making the Radio: The Tuning Capacitor
Our capacitor was constructed from half a saucepan and a semi-circular metal
plate (make sure all edges are filed smooth). The metal plate should be
just a little bigger than the base of the saucepan, with a 2-3cm (about 3/4-1 inch)
diameter semi-circular hole cut out from the middle of its straight edge. Screw this
plate at its corners to the wooden base.
Place a piece of heavy-duty plastic sheet over the plate and tack or tape it down
to keep it from slipping around.
The saucepan should be fixed above the plastic-covered metal plate by a bolt.
Use washers to ensure that the spacing is as small as possible but not so
tight that it can't move. Pass the bolt through the semi-circular hole
in the bottom plate to avoid making electrical contact. Use the saucepan's
handle to tune the radio by varying the overlap between the metal plate
and the saucepan. Run a flexible wire from connector E to the saucepan,
and from connector A to one of the fixing screws on the bottom plate.
The detector and earpiece