| 摘要 |
<p>PURPOSE:To reduce the size and cost of the device by connecting the part between the base and emitter of a transistor(TR) for switching in series between the collector and emitter of a light receiving TR and operating the TR for photodetection in an active area. CONSTITUTION:The part between the base and emitter of the switching TR4 which uses an NPN TR is connected to the light receiving TR in series, and a 1st DC power source 6 is connected thereto. When the voltage of the 1st DC power source 6 is denoted as V1 and the base-emitter voltage of the switching TR 4 is denoted as VBE*, the collector-emitter voltage VCE of the switching TR 4 is V1-VBE*. Here, VBE* is a low value or about 0.6-0.7V, so VCE is close to the voltage V1 of the 1st current source 6. Therefore, the light receiving TR is used in the active area. Therefore, the switching speed of the photocoupler 2 is improved greatly.</p> |
