| 摘要 |
PURPOSE:To improve rise time and fall time of photooutput wave in intensity modulation time of a luminous element, by providing a spike generation circuit between a photo communication luminous element and a transistor which drives the element. CONSTITUTION:When connecting a luminous element 38 with a luminous element driving transistor 36 having an input terminal 31, a spike generation circuit 34 is interlaid between them. This circuit 34, which is composed of a resistor 32 having a required resistance value and a capacitor 33 and also a coil 37, connects the resistance 32 to the cpapacitor 33 in series, and a circuit in which the coil 37 and the element 38 are connected with each other in parallel is connected to the circuit 34. Further, the resistor 32 and the element 38 are grounded, a collector of the transistor 35 is connected to the junction point between the capacitor 33 and the coil 37, and voltage -VBB is impressed onto an emitter through the resistor 36. It is possible, in this manner, to largely improve rise time and fall time of photoinput wave of the element. |
