如图所示电路，光电耦合器4N 25 起到耦合脉冲信号和隔离单片机89C 51 系统与输出部分的作用，使两部分电流相互独立。输出部分的地线接机壳或大地，而 89C 51 系统的电源地线浮空，不与交流电源的地线相接，这样可以避免输出部分电源变化对单片机电源的影响，减小系统所受的干扰，提高系统可靠性。 CNY17 Optocoupler. +---+--+---+ A |1 +--+ 6| B K |2 CNY17 5| C |3 4| E +----------+ HDSP-L101, HDSP-L201, HDSP-5401, TC07-11 Common row anode 5x7 dot matrix LED display. +---+--+---+ Col1 |1 +--+ 12| Row1 Row3 |2 11| Row2 Col2 |3 5x7 10| Col3 Row5 |4 LED 9| Row4 Row6 |5 8| Col5 Row7 |6 7| Col4 +----------+ HDSP-L103, HDSP-L203, HDSP-5403 Common row cathode 5x7 dot matrix LED display. +---+--+---+ Row1 |1 +--+ 12| Col5 Row2 |2 11| Row3 Col2 |3 5x7 10| Row4 Col1 |4 LED 9| Col4 Row6 |5 8| Row5 Row7 |6 7| Col3 +----------+ TIL111, TIL112, TIL116, TIL117, TIL118, TIL124, TIL125, TIL126 Optocoupler. +---+--+---+ A |1 +--+ 6| B K |2 5| C |3 4| E +----------+ TIL113, TIL119 Optocoupler with darlington transistor output configuration. +---+--+---+ A |1 +--+ 6| B K |2 5| C |3 4| E +----------+ TIL192 Dual optocouplers. +---+--+---+ 1A |1 +--+ 8| 1C 1K |2 7| 1E 2A |3 TIL192 6| 2C 2K |4 5| 2E +----------+ TIL193 Quad optocouplers. +---+--+---+ 1A |1 +--+ 16| 1C 1K |2 15| 1E 2A |3 14| 2C 2K |4 TIL 13| 2E 3A |5 193 12| 3C 3K |6 11| 3E 4A |7 10| 4C 4K |8 9| 4E +----------+ TIL198 Dual optocouplers with darlington outputs. +---+--+---+ 1A |1 +--+ 8| 1C 1K |2 7| 1E 2A |3 TIL198 6| 2C 2K |4 5| 2E +----------+ TIL199 Quad optocouplers with darlington outputs. +---+--+---+ 1A |1 +--+ 16| 1C 1K |2 15| 1E 2A |3 14| 2C 2K |4 TIL 13| 2E 3A |5 199 12| 3C 3K |6 11| 3E 4A |7 10| 4C 4K |8 9| 4E +----------+ TIL308 7-segment display with b...
