| 摘要 |
<p>The advertising panel allows any required image or slogan to be displayed in one of several colours. It has an array of separate equilateral triangular cavities, each forming a reflector and containing red, green, blue and white lamps. The latter are wired to a rheostat circuit, for varying the current so that the individual lights are energised to provide the required display. The rheostat is formed by a number of copper sheets (3) glued together and separated by insulating material (2), forming a block, which is perforated with the same number of cylindrical holes as there are lamps, with a spring (5) in each to allow the cursor (1) to move to and fro.</p> |
