| 摘要 |
PURPOSE:To reduce the trailing of the fall of the waveform of emitted light from a light-emitting diode remarkably, and to enable modulation at high speed by mutually connecting collector terminals for an N-P-N transistor and a P-N-P transistor and connecting the light-emitting diode in parallel with the P-N-P transistor. CONSTITUTION:An N-P-N transistor 1 and a P-N-P transistor 4 are connected in series by mutually connecting collector terminals, and a light-emitting diode 5 is connected in parallel with the P-N-P transistor 4 and a pulse signal for controlling the lighting of the light-emitting diode 5 is transmitted directly over a base terminal for the N-P-N transistor 1. Signal conversion means 7, 8 forming forward bias signals to the P-N-P transistor 4 in response to the fall of the pulse signal are connected between base terminals for both transistors. Accordingly, the rise of the control of the lighting of the LED 5 is accelerated because the rise of the N-P-N transistor 1 is fast, and charges stored in the parasitic capacitance of the LED 5 can be discharged through the P-N-P transistor 4, thus also inhibiting the trailing phenomenon of fall. |
