| 摘要 |
<p>The fire detector has two elements (1, 2) one for reference and the other for analysis. The impedances of these two elements (1, 2) vary in the presence of high temperature and/or radiation and/or combustion gases. The reference element is isolated completely or partially from the agents to be detected. The elements (1, 2) are mounted in series and form live adjacent branches of a Wheatstone bridge. The other two branches of the bridge have resistances (R1 R3) in them. In the diagonal connecting the common points (X, Y) of the resistances and the elements is an alarm system which is actuated when there is a voltage imbalance. The elements (1, 2) are ionisation chambers containing a radioactive material.</p> |
