Its purpose in life was to be the local oscillator and mixer in AM radios, and a kazillion of them were made to fill that purpose.

它本来是被用作调幅收音机中本振和混频管，并且被大量出来以实现这个用途。

The maximum of B along elevation direction is closely under the central section of coil.The B of equiamplitude magnetic field is increased by increasing of the output current ...

等幅高频磁场磁感应强随高频电源输出电流增加而增加,磁场调幅处高磁场内磁感应强,高调幅波信号幅值电压,可有效高磁场内磁感应强。