ĐIỆN tử VIỄN THÔNG DTVT2 nhom7 bai5 txt khotailieu

Nhóm Nguyễn Bá Duy Trần Minh Đức Đỗ Văn Sang Nguyễn Khắc Ngân Dương Văn Hùng Vũ Văn Chinh Task 1: Task 2: Here is a diagram of an alarm system in the house It have detection device a passive infra-red detector b Pressure mat c Window foil d Sense circuit e Door switch f Bell g Key operater switch control box h power it is a warning system so when you coming the house, the door was open then the bell maybe ring because it makes it easier to turn on, turn off or security 5 When the door switch, window foil pressure mat be broken then the bell is ring Task 3: Task 4: Task 1: Aburglar discnnect the supply._ C: The alarm continues to operate on batteries: Battry backup 2: The glass is broken _ E:The foil breaks too Break detectors 3: A door is opened _ F:A magnet on the door trigs a switch on the trame Maghetic switches 4: A windown is opened _ A:a magnet on the moving past trigs a switch ; Magnetic switches 5: You’re not thre to resetthe system _ G:the alarm stops after a set time Autumatic cut-off 6: A burglar tries to force the alarm open _ B:Tamper sensors trigger the alarm Tamer wotection 7: Someone steps on them _ D:Two thin metal plates come in contact : Pressure mats Task if pressure mats are tantly walked on, a door is opened if you fit an exit delay, you won’t set off the alarm when leabing or returning to the house if your system doesn’t have an automatic cut-off, the alarm won’t stop and the noise will go on for hours if a burglar walks in front of a motion sensor, vibration sensors will respond if the glass is broken the foil breaks too 6 Tamper sensors will trigger the alarm if a burglar tries to force the box open A magnet on the moving part trips a switch if a window is opened The alarm stop after a set time if you’re not there to reset the system Task 8: Intergrated f circuit Circuit j diagram Alternating f current Primary b cell Zener e diode Remote i control Reed e switch Surface k wave Vibration a sensor 10.Reverse h bias 11.mains d supply Task 9: Sensing device Used to detect LDR light Thermistor Heat Microphone sound When the light falls on the LDR It’s resistance deceases This causes the base voltage of the transistor and the bias current to increase It’s using for adjust the sensitivity of the input Term Opposite Cut of Saturation Fixed resistor Variable resistor increases Decreases energize De-energize Slow Rapid To cause Prevent Forward bias Reverse bias To prevent the transistor, a diode is connected in reverse bias across the delay Task 10: The diagram shows a reed switch The reeds sealed in a glass envelope to protect them Because it helps to prevent corrosion of the contacts When a magnet is brought close to the reeds, they are magnetized, attract each other, and close When the magnet is removed, the reed open