During the college entrance examination and high school entrance examination held as scheduled every year, some schools will be designated as examination rooms. During the construction of standardized examination rooms, these schools will purchase and install a large number of mobile phone jammers. How to solve it?
Most of the mobile phone jammers used in the standardized test room are low-power mobile phone signal jammers. Its RF transmission power is usually 2-3W for each frequency band, and the total RF transmission power of the whole machine is about 30W. The overall power consumption of a mobile phone jammer is roughly in the range of 120-200W. The mobile phone jammer itself will be equipped with a switching power supply (or a power adapter), which is used to convert the AC 220V into 5V or 12V DC to provide power consumption for the device.
Because there will be dozens or even hundreds of exam classrooms in a school, the number of mobile phone jammers is corresponding to it. In order to turn on or off such a large number of mobile phone jammers in a centralized manner, the easiest way is to concentrate the power supply of all mobile phone jammers in each teaching building on one AC power supply line.
However, in many standardized test classrooms, monitoring systems, closed-circuit television systems, and campus broadcasting systems are installed at the same time, and these devices are usually equipped with switching power supplies. The power supply of the jammer should be powered by the DC on the monitoring line? The purpose of doing this is to save a part of the switching power supply and the cost of power line layout.
This method is not advisable, the main reason is: the power consumption of each mobile phone jammer is not low, when using AC 220V power supply, the current in the power line is close to 1A, multiple mobile phone jammers are connected in parallel When the power line is on, the total current value will only accumulate slowly. If it is replaced with a DC power supply, according to the conversion of power consumption, current and voltage, the current occupied by a single mobile phone jammer will reach 10-20A. When multiple mobile phone jammers are connected in parallel on a DC power line, the total current It will reach hundreds of A, which is obviously not in line with the correct circuit usage specification.
