| 摘要 |
PURPOSE:To obtain a bipolar logic circuit whose number of elements and number of wirings are small, and whose circuit constitution is simple, by using that which has two pieces of emitters, as the second transistor, and connecting the first emitter, and the second emitter, to a base of the third transistor, and an output control signal line, respectively. CONSTITUTION:When an output control signal line 4 is in an 'H' state, an output terminal 3 becomes an 'H' or 'L' state by an input to a base of the first transistor 5. On the other hand, when the output control signal line 4 is set to an 'L' state, the second transistor 7a always becomes a conducting state irrespective of a conducting or non-conducting state of the first transistor 5, because its second emitter is connected to the output control signal line 4, and a current flows to the output control signal line 4. Accordingly, the third transistor 8 becomes a non-conducting state, and also, the collector potential of the second transistor 7a falls, and the fourth transistor 9 and the fifth transistor 10 become a non-conducting state. As a result, an output terminal 3 becomes a high impedance state. |
