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18     ཥɿཥ༩ྼ୦


                (̬)  ཥ౺᜗කᗫʘᏐ͜ķLED ᚨਗཥ༩


                          ཥ౺᜗කᗫᏐ͜ί೯Έɚ฽᜗(LED)ᚨਗཥ༩dνྡ 2-3 הͪdՉ
                     ʈЪत׌Ⴍ׼νڌ 2-3f



                                                                  ڌ 2-3  ʈЪत׌


                                                       V i ໤Ҝ           Hi            Low

                                                       ණ࢛฽             ೵路             ක路
                                                     කᗫत׌              (ON)          (OFF)

                                                        LED             亮              ฮ

                                                         I C           I C(sat)         0

                                                        V CE       V CE (sat)Ø0.2V     V CC

                                                    ཥ౺᜗狀࿒              ཱིձ             ࿚˟


                        ྡ 2-3 ཥ༩ྡ




                          ೯Έɚ฽᜗ίනΣ਋Ꮐɨ೯ΈdՉන਋Ꮐࠥߒ 1.5~2.5 Vd௰ɽτ

                     Όཥݴމ 50mAdԴࣛ͜඲ЕટࠢݴཥڜfԷνྡ 2-3 הͪj
                      (1)߰ LED ʈЪί 1.8Vd20mA ࣛdණ฽ཥڜމ
                                V   − V    − V         15 −  8 . 1 −  2 . 0
                         R C  Ø   CC   LED    CE ( sat )  Ø         Ø650 Ωf
                                         I C               20 m
                      (2)߰ V BE(sat)Ø0.8VdƺØ100dԴཥ౺᜗ཱིձٙ௰ʃਿ฽ཥݴf

                                   I C
                         I B(min)Ø    Ø200 μAdۆ
                                   β
                                   V − V
                         R B(max)Ø  i    BE (sat )  Ø21 kΩf
                                      I B (min )
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