| 摘要 |
<p>PURPOSE:To make it unnecessary to provide an independent power source for compensating current and make a used transformer small-sized, by using effectively the DC current itself flowed to a hybrid circuit. CONSTITUTION:A transformer 1 is the hybrid transformer and has terminals 21 and 22, which are connected to a telephone set through a subscriber's line, and terminals 23, 24, and 25 connected to a four-wire circuit. When the telephone set is hooked off, a DC current is supplied from a power transformer 1, and simultaneously, it is stopped by a capacitor 2 so as to have no bad influence upon the voice signal, and the current shunted through resistances 3 and 4 is detected by a DC current detector 6. At this time, since the magnetic field generated by DC currents of windings 1-1 and 1-2 of the transformer 1 is cancelled by the compensating current flowed to an additional winding 1-3 of the transformer 1, the DC magnetic field in the iron core has only by a little residual.</p> |
