| 摘要 |
<p>A combustion detection device is disclosed that senses the presence of a fire and provides an alarm indication of the same by essentially shorting the input leads from a power supply. An ionization detector is utilized to sense the products of combustion and provide an output indicative thereof, which output is coupled through a field effect transistor to an operational amplifier where the output is compared with a reference voltage that can be varied as desired. When an output from the ionization detector supplied through the field effect transistor exceeds the reference voltage, an output is provided from the operational amplifier to a triggering circuit connected between the power supply leads to essentially short the leads as an alarm indication of a sensed fire condition. A light-emitting diode is connected to the triggering circuit to give a visual alarm indication, and calibration leads are also provided to facilitate calibration of the apparatus. The triggering circuit, in one disclosed embodiment, includes a pair of transistors connected to the drive and sink outputs of the operational amplifier, while in a second disclosed embodiment, the triggering circuit includes a silicon controlled rectifier.</p> |
