Sometimes a rheostat is made from resistance wire wound on a heat-resisting cylinder, with the slider made from a number of metal fingers that grip lightly onto a small portion of the turns of resistance wire.
32.
The salt water rheostat operates at unity power factor and presents a resistance with negligible series inductance compared to a wire wound equivalent, and was widely used by generator assemblers, until 20 years ago, as a matter of course.
33.
Where the rheostat must be rated for higher power ( more than about 1 watt ), it may be built with a resistance wire wound around a semicircular insulator, with the wiper sliding from one turn of the wire to the next.
34.
Around 1832, Hippolyte Pixii improved the magneto by using a wire wound horseshoe, with the extra coils of conductor generating more current, but it was AC . Andr?Marie Amp�re suggested a means of converting current from Pixii's magneto to DC using a rocking switch.
35.
You start to get more of a problem as you come down the spectrum to lower VHF and MW but you still might be able to avoid a messy insertion into a leg bone by using fine guage copper wire wound on a ferrite core.
36.
Already, at the Miller show on Monday, Dalton had to face 19-year-old Shanna Shank, who walked backstage with her hair upswept in a bee's nest style with about 3 feet of wire wound around her head ( a souvenir from a previous fashion show ).
37.
In typical experiments, students measure the slower time of fall of the magnet through a copper tube compared with a cardboard tube, and may use an oscilloscope to observe the pulse of eddy current induced in a loop of wire wound around the pipe when the magnet falls through . to use of multiple magnets.
38.
The spin axis could be oriented to within 1 2?accuracy by the use of a magnetic attitude control device, consisting of 250 cores of wire wound around the outer surface of the spacecraft . The interaction between the induced magnetic field in the spacecraft and the earth's magnetic field provided the necessary torque for attitude control.
39.
The canonical example of the design can be seen in the small tabletop ST device made at Flinders University, which uses a central column made of copper wire wound into a solenoid, return bars for the toroidal field made of vertical copper wires, and a metal ring connecting the two and providing mechanical support to the structure.
