| 摘要 |
A solid state smoke detector system comprising transmitting means including a lamp disposed on one side of a medium, whose opacity is to be monitored, for providing a constant intensity of light and receiving means including a photoelectric detector disposed on the other side of the medium for receiving light from the lamp. The transmitting means includes a voltage-controlled, constant-current source for providing a constant current to the lamp. Receiving means are provided and comprise a balanced, current-to-voltage converter coupled to an intermediate amplifier to provide a voltage signal which is a linear function of the light received by the photoelectric detector. The voltage signal is provided to a meter driver circuit for driving an indicating meter to thereby provide an indication of the opacity of the medium. The meter driver circuit includes a voltage-controlled, constant-current source. The voltage signal is also provided to a comparator circuit which provides an alarm signal when the voltage signal exceeds a predetermined level.
|
