| 摘要 |
An ionization smoke sensor including a pair of ionization chambers normally biased to maintain an ionic current which varies in response to smoke particles within one of the chambers. A normally non-conductive transjstor is biased to conduct when an impedence change of the combination of ionization chambers, caused by the smoke, exceeds a certain amount. The conductive transistor biases a thyristor to conduct an alarm cct.. A comparator cct. is connected between the transistor and the thyristor for providing a biased signal. The biased signal is not applied by the comparator until the cur-rent through the conductive transistor exceeds a certain threshold value.
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