| 摘要 |
<p>A soldering iron (10) is temperature controlled by temperature control circuitry (20) in handle (16). The temperature setting of the iron is changeable only by the replacement of a laser trimmed highly accurate resistor in the control circuitry establishing the set temperature. A removable key (50) plugged into a socket (24) at the junction of the handle (16) and a tube (14) supporting the tip (12) carries the resistor. In order to change the set temperature the handle (16) must be disassembled from the tube (14) to replace the key (50), with another key carrying a resistor establishing a different set temperature. The key (50) is visible through a window (38) in the handle (16) and is marked to indicate the set temperature to be maintained by the control circuitry. Thus, a soldering iron having both accurate temperature control over a range of preselected temperature and protection against on-station worker adjustment of soldering tip temperatures to other than those prescribed is provided.</p> |
