| 摘要 |
PURPOSE:To replace a letter coil with a small one, by erasing DC magnetic field occurred with each other by setting the current in the same direction in the letter coil, fellow of telephone. CONSTITUTION:A capacitor 4 is installed between a letter coil 3 and a telephone 1 and install letter coils 5 and 6 on the both extremes of the capacitor 4. A letter coil 5 is connected to the letter coil 3 and connect a letter coil 6 to a negative power source. Then, DC current is flowed in order of letter coil 2 telephone 1 letter coil 5 letter coil 3 letter coil 6. Therefore, in the letter coils 2 and 3, and 5 and 6, as shown in the figure with an arrow mark, a current is flowed in the same direction and respective DC magnetic fields occurred are erased. By this reason, the condition of the letter coils 2 and 3, and 5 and 6 becomes the same condition as that a current does not practically flow in. Then, even if the voice signal is doubled, the margin to a saturation point becomes large and letter coils can be replaced with small ones. |
