| 摘要 |
<p>SMOKE DETECTORS The invention relates to smoke detectors of the kind comprising first and second electrodes defining an ionisation chamber permitting entry of smoke, said ionisation chamber being optionally divided into two regions by a collector electrode, a radioactive source to ionise gas in the ionisation chamber and a potential difference applied across the first and second electrodes to cause an ion current to flow, which current is affected by entry of smoke, and provides an auxiliary electrode positioned in the ionisation chamber, and means to maintain or create a potential difference between the first electrode and the auxiliary electrode. The auxiliary electrode may be used for testing or for adjustment of sensitivity.</p> |
