Buying a metal detector is not easy. If you have not done it before, you need to understand that there are many things that need to be considered. If you have bought metal detectors once before and you want to have them checked or buy a new and improved one, you need to do your research properly.
The first thing to consider when buying a detector is the place where you want to use it. Sure you will buy it for security but the level of security at an airport or a government building will be significantly higher than the security concerns at a football match. Why? Lets take an example, chemicals are not allowed on the planes because there is always a chance that they will be used in some way to create a bomb. But you might be allowed to take perfume bottles and other such sprays to a football match.
The next thing to consider is how often the system will be used. For example, airport metal detectors will be in use 24/7 and the metal detector in school needs to active only during school hours. Therefore the metal detectors have to be in running condition all the time. This can be determined by timely maintenance checks that can help in an efficient running of the device.
Metal detectors work on different frequencies. You must wonder what frequencies are. Frequencies of the detectors are the number of times signals are transmitted and received by the detector in one second. Since the basic detector works with electromagnetic fields that are produced due eddy current from the AC motor, the number of signals are calculated in KHz or kilo hertz.
For example if a detector is operating at 5 KHz, it will transfer signals 5000 time per second. These frequencies help in determining how sensitive the detector may be to certain objects. Have you ever wondered why small objects like coins are asked to be removed from pockets at an airport security check point? It is because the metal detectors are at high frequency and the alarm will go off and you will be requested to step aside for a thorough physical pat-down.
Low frequency detectors are better at rejecting trash and have a better sensitivity when it comes to metals like copper and silver. Most general purpose metal detectors have low frequencies.
In case your wondering, having a detector at high or low frequencies is perfectly safe for any individual to walk through.