| 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 currebt itself flowed to a hybrid circuit. CONSTITUTION:A transformer 1 is the hybrid transformer and has terminals 23, 24, and 25 connected to a outgoing trunk circuit through a trunk line. The DC current indicating the operation state of the trunk line is stopped by a capacitor 2 for the purpose of preventing the bad influence of the outgoing trunk circuit upon the voice signal when a switch 12 is closed, and this DC current is supplied to windings 1-1 and 1-2 of the transformer through one out of a resistor 3 and two parallel connected current mirror circuits which is selected automatically by the polarity of the outgoing trunk circuit. At this time, since the magnetic field generated by this DC current is cancelled by the compensating current flowed to an additional winding 1-3, the DC magnetic field in the iron core has only a little residual.</p> |
