Burglar alarms work by using electrical circuits and sensors to detect intruders. There are types of burglar alarms including motion detectors, which identify changes in position in a specific area, and smoke or fire alarms, which detect possible arson. There are also panic detectors which detect movement changes in a particular area.Know More
A basic burglar alarm contains an electric circuit connected into an entryway, with a switch that opens or closes the circuit. The switch detects acts of intrusion such as opening a window or door. This kind of alarm is built into an entryway. It is classified into two categories. The first is an open-circuit system, in which the circuit is closed and electricity flows when the door is opened. Completion of the circuit triggers the alarm. The second type is a closed-circuit system, wherein the circuit is closed when the door is shut. The circuit opens when someone opens the door, thus triggering an alarm.
In some burglar alarms, sensors are attached to a central unit that sends out a signal upon identifying any intrusion, fire or panic. Signals are typically sent in the form of loud noise. Modern burglar alarms send signals through the Internet or via telephone lines. The homeowner becomes alerted whenever a possible intrusion is identified. Typically, advanced alarm systems send an automated email or phone call to inform a person of any suspicious activity at home.Learn more about Doors, Windows, & Locks
Telegraph keys are switches in electrical circuits that power on the current. When the operator taps out the signals for a word, the switch finishes a circuit, permitting electricity to continue around it. At the other end of the line, the recipient watches a pointer or dial indicating the different patterns of code, listens to a buzzer or reads the print out from a device.Full Answer >
Insulation slows or prevents heat, sound, electricity, mechanical vibration or radiation from coming through walls. There are four types of insulation: heat insulation, sound and vibration insulation, electrical insulation, and radiation insulation.Full Answer >
Wireless doorbells use a radio transmitter to send a signal to a receiver, which activates the sound or chime alerting the occupant that someone is at the door. Unlike traditional doorbells that make the alert using electromagnets to activate plungers against tone bars, most wireless doorbells use a prerecording of chimes.Full Answer >
Electrochromic glass works by moving ions in one layer of glass through an inner separator layer and into another layer of glass through the use of electrodes sandwiched in the layers. Once the ions are on the other side of the window, they filter light by creating a tint of a certain color. When electricity is applied again, they migrate back to the other side, making the window clear again.Full Answer >