| 摘要 |
<p>The control knob is mfd. from a variety of rare earth materials which have a thermal conductivity which is above that of thermoplastics and approaches that of metals. The user thus gains the impression of a higher quality article, as compared with the "feel" of purely plastic items. The material used can be either ceramic or porcelain which is given a metallised coating or matt finish. Where complete electrical isolation is required, the metallisation covers only a part of the knob, or an insulating bush is used. A spring insert holds the knob on the control shaft.</p> |
