Fire detector
First Claim
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1. A photoelectric type fire detector comprising:
- a light-emitting section for generating pulsed light for detecting smoke;
a light-receiving section, having a first variable resistor, for receiving scattered light from the light from said light-emitting section caused by the smoke, amplifying a light-receiving output, and adjusting a gain;
an A/D converting circuit for converting the light-receiving output from said light-receiving section into digital signals; and
a signal transmitting section, having an operation indicating lamp, for transmitting the digital signals having been converted in said A/D converting circuit;
wherein said light-emitting section comprises a light-emitting element for detecting smoke, an oscillating circuit for making said light-emitting element emit light by supplying a pulse output thereto, and a pulse width expanding circuit for expanding a pulse width of the pulse output from said oscillating circuit and outputting it to said operation indicating lamp.
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Abstract
A fire detector capable of readily and accurately adjusting the sensitivity there of and of not erroneously outputting any fire signal is provided with a first-stage amplifying circuit having an output adjusting variable resistor and a fire discriminating section having a reference voltage adjusting variable resistor. As a result, it is possible to adjust the amplified output to a predetermined value by the switching level of the fire discriminating section to a predetermined value by the reference voltage adjusting variable resistor.
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Citations
2 Claims
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1. A photoelectric type fire detector comprising:
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a light-emitting section for generating pulsed light for detecting smoke; a light-receiving section, having a first variable resistor, for receiving scattered light from the light from said light-emitting section caused by the smoke, amplifying a light-receiving output, and adjusting a gain; an A/D converting circuit for converting the light-receiving output from said light-receiving section into digital signals; and a signal transmitting section, having an operation indicating lamp, for transmitting the digital signals having been converted in said A/D converting circuit; wherein said light-emitting section comprises a light-emitting element for detecting smoke, an oscillating circuit for making said light-emitting element emit light by supplying a pulse output thereto, and a pulse width expanding circuit for expanding a pulse width of the pulse output from said oscillating circuit and outputting it to said operation indicating lamp.
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2. A heat-photoelectric type fire detector comprising:
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a light-emitting section for generating pulsed light for detecting smoke; a light-receiving section, having a first variable resistor for adjusting an output, for receiving scattered light of the light emitted from said light-emitting section; a heat detecting section for detecting heat by a heat-sensitive element; an A/D converting circuit for converting the output from said light-receiving section and a detected output from said heat detecting section into digital signals; and a signal transmitting section, having an operation indicating lamp, for transmitting the converted digital signals from said A/D converting circuit; wherein said light-emitting section comprises a light-emitting element for detecting smoke, an oscillating circuit for making said light-emitting element emit light by supplying a pulse output thereto, and a pulse width expanding circuit for expanding a pulse width of the pulse output from said oscillating circuit and supplying it to said operation indicating lamp.
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Specification