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Sensors / Detectors: Smoke Detectors
Sensors / Detectors -- Main Page
Last Updated on:
Friday, October 16, 2009 03:42 AM |
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Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
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Circuit forms gamma photon detector - 04/24/03 EDN Design Ideas /
(added 1/05)The circuit of Figure 1 includes a PIN photodiode that detects individual
photons of gamma radiation. The reverse bias on the photodiode sometimes creates a
depletion region. When such a photon strikes this depletion region, a small amount of
charge develops. This charge is proportional to the photon's energy.... |
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LDR & LED Smoke Detector - Smoke detectors are generally used in advanced alarm
systems. Most of this professional devices use gas-detectors, ionization rooms or
radioactive elements as sensors. In this circuit we are not using any of this
complicated components. Instead of these, we are using two LDRs and one LED. LM1801
special-purpose IC ,which is designed especially for smoke detectors, provides us
building this circuit by using the minimum number of components. It includes one
internal zener supply, two reference voltage outputs, one voltage comperator, fixing
diodes and one 500mA output transistor. ….(circuit design added 11/08) |
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