| 摘要 |
PURPOSE:To transmit an ideal dial pulse without any change in the brake rate due to a line resistance by disconnecting a capacitor of a DC shunt circuit from the circuit when a relay for forming a DC loop is turned off. CONSTITUTION:A relay K2 activated in synchronizing with a relay 3 for forming a DC loop is added. Thus, even if the relay 3 is turned off at a time T1 and a voltage is not impressed to a DC shunt circuit 4, the capacitor C2 is disconnected from a base of a transistor (TR) by the turning off of the relay K2 connected in series therewith. Thus, a voltage VC2' after charging of the capacitor C2 holds a voltage at the time T1 continuously for the time of T1, T2. When the relay 3 is turned on at the time T2 and the voltage is impressed again to the circuit 4, a collector current flows immediately to the TR. As a result, a station current IL' is an ideal discontinuous waveform having a steep leading characteristic without delay to the interruption of the relay 3 and the brake rate of the dial pulse due to the line resistor R2 is unchaged. |
