During the annual college entrance examination and high school entrance examination as scheduled, some schools will be designated as test classrooms. During the construction of standardized test classrooms, these schools will purchase and install a large number of test classroom jammers. Then, a large number of test classroom jammers, How to solve this problem in the power supply?

Most of the test classroom jammers used in standardized test classrooms are low-power mobile phone signal jammers. Its radio frequency transmission power is usually 2-3W per frequency band, and the total radio frequency transmission power of the whole machine is about 30W. , and the overall power consumption of an exam classroom jammer is roughly in the range of 120-200W. The test classroom jammer itself will be equipped with a switching power supply (or a power adapter), its function is 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 test classrooms in a school, the number of test classroom jammers corresponds to it. In order to turn on or off so many test classroom jammers in a unified and centralized manner, the easiest way is to concentrate the power supply of all test classroom 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. These devices are usually equipped with switching power supplies. Therefore, some customers ask whether they can take the test. The power supply of the classroom jammer should be powered by the DC on the monitoring line instead? The purpose of this is to save a part of the cost of switching power supply and power circuit layout.

This method is not desirable. The main reason is: the power consumption of each test classroom jammer is not low. When using AC 220V power supply, the current in the power line is close to 1A, and multiple test classroom jammers are connected in parallel. When on a power line, the total current value only accumulates slowly. If it is replaced with DC power supply, according to the conversion of power consumption, current and voltage, the current occupied by a single test classroom jammer will reach 10-20A. When multiple test classroom jammers are connected in parallel on a DC power line, the total The current will reach hundreds of A, which obviously does not meet the correct circuit usage specifications.