| 摘要 |
<p>PTC electrical heating devices are disclosed which are suitable to vaporize air treatment chemicals from an impregnated slab, such as insect repellents. In one form an electrical contact to a PTC heater element is provided with a bowl-shaped contact head to reduce the risk of edges of the contact cracking the heater element. In other forms peg and recess structures interact with apertures on a heat transfer plate to facilitate assembly of the parts of the structure.</p> |
