The XH-101P explosion-proof cell phone jammer

For shielded wire, usually multi-strand braid, in the same volume because greater surface area 3. Shielded coaxial cable used for analysis of the application in practice is very common, its shielding, separate discussion is necessary. Coaxial cable used in an electric field to inhibit the capacitive coupling is very effective, but in the magnetic coupling, the coaxial cable interference problem more complicated. The complex is located by the coaxial cable center conductor and shield layer, under certain conditions can form a shield and center conductor of the magnetic coupling. Analysis are as follows: (1) coaxial cable center conductor is affected by sensor, in order to facilitate the analysis, as no current flows through the center conductor, while the shielding layer has a uniform axial current IS flowing.cell phone jammer helps to stop students sending messages during the class. Then the self-inductance of the shield have L s = φ / Is, shield and center conductor mutual inductance between the M = φ / Is, as the magnetic flux generated by all IS surrounded by a central wire, so the above two equations of φ equal. V s is the external factors in the voltage induced on the shield, Is V s is generated by the current, combined with the shield self-inductance L s and the resistance (Rs) exist, so Is the center conductor had induced voltage.XH-101P explosion-proof cell phone jammer is mainly applied in gas station, oil house, gas factory, etc. When the shielding current in the center conductor will sense a voltage V n, the voltage at frequency ω ≥ 5ωc close to the shield when the voltage on the VS, and increases as the frequency increases. We will shield grounded at both ends of the magnetic coupling can not suppress interference, because the shield of the current generated by the magnetic flux will be cross-linked with the center conductor. Usually only the charge induced on the shield drain into the ground, played the electric field shielding effect. (2) coaxial cable center conductor is the source of interference, that there is current flowing through the center conductor. At this time, such as the shield grounded at one end, then the center conductor in the charge induced on the shield to be leaked into the ground, played a role in shielding the electric field, but the magnetic field, its effect is very small.The XH-101P explosion-proof cell phone jammer is mainly applied in inflammable and explosive occasions. If the shield grounded at both ends, as shown by the conductor if the center frequency ω is much larger than the current I1 of the cut-off frequency ωc shield, the shield will be close to the external magnetic field current IS nearly cancel each other, played a magnetic radiation purposes. And low frequencies, is ineffective. Of course, this IS the connection method can not make the whole equal to I1, the current IC as well as to shunt effect. For IS = I1, can be used connections, I1 no other return than the slip road outside the IS, making the IS and I1 equal and opposite. The magnetic field generated between the two cancel each other, thereby restrain the magnetic field radiation purposes. Whether high or low frequency of this connection has a good shielding effect. This cell phone jammer forms blocking magnetic field in appointed area.A weak signal by the amplifier schematic, where E1 is a signal source and its input common-mode noise voltage of the earth, E2 is the source side to side with the potential difference amplifier noise signal, C is the shield or the shield of the distributed capacitance . Figure (a) shows the circuit, the shield wire is connected with the shield grounded at the signal.