| 摘要 |
<p>PURPOSE:To control the rise in cost at a low level even when the number of luminous (light-receiving) elements is increased by making groups of light-receiving elements correspond to groups of luminous elements respectively, driving optional one of the groups of luminous elements selectively, and thereby enabling input of the output of all the light-receiving elements into one amplifying circuit. CONSTITUTION:Collectors of phototransistors 21-2n are connected commonly and inputted in the amplifying circuit 3. When control data 8 is latched in a latch circuit 6, normal-direction bias voltage is impressed on the base of one of transistors 71- 7n designated by the control data 8 and thereby the transistors, e.g. 71, is turned on. By this, driving current flows to a luminous diode 11 to make the latter luminous and thus only the output signal of the phototransistor 21 receiving the light from the luminous diode 11 comes out at the output of the amplifying circuit 3.</p> |
