The Challenges of Power Supply for Mobile Phone Signal Jammers in Standardized Examination Rooms

Every year, during the scheduled high school and middle school entrance examinations, certain schools are designated as examination centers. These schools, during the construction of standardized examination rooms, procure and install a large number of mobile phone signal jammers. However, with the large quantity of these devices, how should the power supply be addressed?

Power Consumption of Mobile Phone Signal Jammers:

The mobile phone signal jammers used in standardized examination rooms are mostly low-power devices, with a radio frequency transmission power of 2-3W per frequency band and a total power output of approximately 30W. The overall power consumption of a single mobile phone signal jammer ranges from 120-200W. These devices are equipped with a switch power supply (or power adapter) that converts the AC 220V to DC 5V or 12V, providing the necessary power for the equipment.

Power Supply Challenges:

Due to the presence of dozens or even hundreds of examination rooms within a school, the number of mobile phone signal jammers required is also significant. To facilitate the centralized powering on or off of these devices, the simplest solution is to connect all the mobile phone signal jammers in each teaching building to a single AC power supply line.

Consideration for Other Devices:

However, in many standardized examination rooms, additional equipment such as surveillance systems, closed-circuit television systems, and campus broadcasting systems are also installed. These devices typically come with their own switch power supplies. Some customers have inquired whether it is possible to power the mobile phone signal jammers using the DC power from the surveillance system, in order to save on the cost of switch power supplies and power line arrangements.

Infeasibility of Sharing Power Supply:

This approach is not feasible primarily because the power consumption of each mobile phone signal jammer is not low. When powered by AC 220V, the current in the power line is close to 1A. When multiple mobile phone signal jammers are connected in parallel on a single power line, the total current will gradually accumulate. If the power supply is changed to DC, based on the conversion between power consumption, current, and voltage, the current consumed by a single mobile phone signal jammer would reach 10-20A. When multiple devices are connected in parallel on a DC power line, the total current would reach several hundred amperes, which clearly violates proper circuit usage standards.


In conclusion, the power supply for a large number of mobile phone signal jammers in standardized examination rooms should be addressed by connecting them to a centralized AC power supply line. Attempting to share the power supply with other devices, such as surveillance systems, is not recommended due to the high power consumption of the jammers. It is crucial to adhere to proper electrical circuit usage standards to ensure the safe and efficient operation of these devices during examinations.