Ask Experts Questions for FREE Help !
Ask
    jessi_goldstein's Avatar
    jessi_goldstein Posts: 1, Reputation: 1
    New Member
    		  
    #1

    Apr 24, 2007, 05:07 PM
    The physics behind a smoke detector?
    I am doing a physics "how things work" project on a smoke detector, and I need to get in contact with an "expert" on them, who knows how they work, and the physics behind them. If someone could help me out.
    Capuchin's Avatar
    Capuchin Posts: 5,255, Reputation: 656
    Uber Member
    		  
    #2

    Apr 24, 2007, 11:30 PM
    Basically, they have a small alpha radiation source, a small air gap, and a radioactive detector.

    The detector triggers if the counts/second measured at the detector is lower than a threshold amount.

    If smoke passes through the airgap, all the particles in the smoke absorbs and scatters some of the alpha particles, meaning that the detector drops below the threshold level, and the alarm sounds.
    SameOldSituation's Avatar
    SameOldSituation Posts: 66, Reputation: 32
    Junior Member
    		  
    #3

    Apr 26, 2007, 01:37 PM
    Is there no other way to do this cheaper? Like... a photogate system or something?

    I don't know... maybe that would not be cheaper.
    Capuchin's Avatar
    Capuchin Posts: 5,255, Reputation: 656
    Uber Member
    		  
    #4

    Apr 26, 2007, 01:59 PM
    The radiation detector is in fact cheaper than an optical sensor. It can also detect smoke particles that are too small to attenuate light.

    All the radtiation detector needs is a radioactive source, and 2 electrodes.
Not your question? Ask your question View similar questions
 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Motion detector installation? [ 4 Answers ]

I am trying to install a motion detector in my house, but when I look at the siring diagram, I can' figure it out. The detector has three wires, 2 black and one green. I understand the green is the ground and one black is the hot and the other black is the neutral, but what I don't understand is...

Motion Detector to Sprinkler transformer question [ 3 Answers ]

Hi, I want to hook a sprinkler valve up to a motion detector. The motion detector (Heath Zenith SL-5316) will put out "up to" 500W, and 4.2A (120 VAC). The sprinkler valve (Orbitz 57020) requires 18VAC min, but is spec'd at 24VAC to draw 0.35A when it switches and 0.23A when it is holding. ...

Why does the motion detector has a limited range 0.5 to 4.5m? [ 4 Answers ]

hi everyone~~ it's my first time here^^ I Need help for homework~~! :confused: I just did a lab which uses the Vernier Motion Detector to find the terminal velocity of a filter when it is released from the rest right below the detector to the ground, and here's the question: why does the...

Wiring a motion Detector into a 3 way system [ 8 Answers ]

I want to install a single motion detector in my garage to control the two lights.the lights are controlled by two 3 way switches one in the garage and one just inside the door inside the house.Can I install the single detector at one of the lights to control them both in this system?

View more questions Search