Smoke detector is an apparatus which detects smoke; it is used for commercial, residential and industrial purposes. This device issues a signal to a fire alarm whereas the one used in households issues a local audible alarm from the detector itself. Smoke detectors are usually designed in a disc shaped plastic container having two parts, a sensor to detect smoke and a loud electronic horn to alert people, these devices generally run on a 9-volt battery. Smoke detectors in large commercial areas are powered by the central fire alarm system which gets power by the battery back up; in the local households usually one battery is used for its performance.

There are two types of smoke detectors, ionization detectors and photoelectric detectors. The ionization detectors use an ionization chamber which detects smoke; this type of detector is more commonly used because it is inexpensive and better at detecting a small amount of smoke. It contains a radioactive element called americium which is supposed to be a good source of alpha particles. One of the demerits of Ionization detectors is that it sometimes gives out false alarms than photoelectric detectors as they detect smoke particles which are too small to be visible.

While working, a radiation passes through two electrodes with air filled in the space, when smoke enters the chamber of ionization, the current is disrupted and the particles of smoke gets attached to the ions present inside, the detector senses a sudden drop in the current and sets off an alarm. The physical appearance of a smoke detector wiring is simple, there is a printed circuit board an ionization chamber and a big electronic horn. The ionization detector detects dangerous smokes like carbon monoxide present in the air.

Another type of smoke detector wiring is a photo electronic detector or just a photo beam detector; it uses a beam of light to detect the smoke and on the other side is its detector. When the beam is crossed, it detects the smoke and sets off the alarm. But, the only disadvantage of the detector is that it needs to have a lot of smoke in the area to block the light from the detector and another disadvantage of this detector is, it is very big in size and is very expensive also. It is generally used for commercial and industrial purposes as the ionization detectors are not feasible for the large areas. When the smoke enters the chamber, it scatters the light resulting in some amount of light being hit to the sensor which detects the disrupt and sets off the alarm. Photoelectric detectors are better at detecting smoky fires than the ionization detectors.

It is very important to choose better smoke detector wiring which have best quality. Smoke detector wiring should always be used in every household and industries, and also for commercial use because even a small bit of spark can ignite a fire which can be responsible for the loss of large number of life and loss of property.