| 摘要 |
<p>A toy car (1) which travels along a flat track (2) is controlled by a carriage (3) which is inside the track and hence hidden from view. The carriage carries a magnet (9) at one end which attracts a piece of magnetic material (10) underneath the front of the car. The track is a hollow rectangle in cross-section, and the carriage travels along the bottom (4). The inside, top and bottom is lined with a metal foil (5, 6). The carriage has contact shoes (7, 8) which are held against the foil layers so as to receive an electric current by which it is driven. The magnet can be an electromagnet which receives control signals.</p> |
