| 摘要 |
PURPOSE:To electrify an input trunk of an opposite station, by providing titled circuit with the a Schmit trigger circuit which is turned on at the detection of the 1st current value and turned off at the detection of the 2nd current value less than the 1st one. CONSTITUTION:When a resistor (r) is shorted by a phototransistor T in a starting circuit through a line (c), current (i) flowing into a resistor ro is set up larger than the 1st current ion which triggers the Schmit trigger circuit ST and switches the output Out from OFF to ON, so that the circuit ST detects the current Ion when a starting contact (a) is closed at an output trunk OGT. Consequently, the output Out is turned on, the input trunk ICT is started and the transistor T is disconnected, so that the resistor (r) is inserted. Thus the current (i) is reduced, but an intermediate value is kept without reduction until the circuit ST is turned off. When the contact (a) is opened, the current (i) disappears and the circuit ST is restored, returning to the normal status. |
