Infrared detector is the most critical part of burglar alarm system directly determines the sensitivity and stability of the system, is the entire system of quality guarantee. China Security manufacturers in these years, both technical mastery and improvement in production capacity were significantly improved, this due to Chinese manufacturers are constantly absorbing foreign product design and production technology, and a focus on reducing costs, making security products began to be contractors were recognized, coupled with the low price for the customer has an important attraction, making rapid domestic growth in the market. Although the quality of domestic and imported products are still gaps, but in the user's security products are not familiar with the case, security products in China is still very competitive.
Many foreign manufacturers are recognized before foreign investors to substantially rely on technology to deal with the cost advantage of Chinese products, but the gap has narrowed in recent years, advantage-decreasing, China technically has gradually caught up with the overseas manufacturers, parts manufacturers more creative ability to launch products with distinctive features, allowing security product quality significantly increased. This phenomenon comes mainly from many manufacturers for brand awareness and the importance of product quality, increased investment and research and development efforts.
Principle and characteristics of infrared detectors
Humans have a constant body temperature, usually at around 37 degrees, will issue a specific wavelength of about 10 μ m infrared, passive infrared detector is by detection of emission from the work IR about 10 μ m. Human emission of infrared of about 10 μ m by Fresnel light filter has been enhanced together in infrared sensor on the source. Infrared sensor sources usually in Pyroelectric elements, such components in receiving the infrared radiation temperature changes the body lose charge balance, release to the external charge, follow-up after testing, the circuit can generate alarm signals.
1. Passive infrared detectors are aimed at the detection of radiation, so the Pyroelectric element infrared radiation of wavelengths of about 10 μ m to be very sensitive.
2. Just infrared radiation human-sensitive, in its radiation the Fresnel face is usually covered with a special filter, lead to significant environmental disturbance control.
3. Its sensors contain two series or parallel each other Pyroelectric element. But two electrodes made of direction is the opposite, environmental background radiation on almost two Pyroelectric components have the same role to produce Pyroelectric effect of offset, so the detector signal output.
4. Once the people within the region intrusion detection, infrared radiation through the body part focusing mirror, and was Pyroelectric Yuan receiver, but two Pyroelectric Yuan receiver to heat different Pyroelectric different cannot be offset through signal processing and alarm.
Advantages and disadvantages of passive infrared probe
Advantages: itself, not any type of radiation, power consumption of the device is small, hidden well, low prices.
Disadvantages: easy to interference from various sources of heat, sunlight; passive infrared penetration is poor, easy to block infrared radiation of human body, can not easily be detectors; susceptible to radio frequency radiation interference, environmental temperature and body temperature approached, detection sensitivity and decreased significantly, sometimes resulting in short-term failure.
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