| 摘要 |
1,181,628. Transistor bi-stable circuits. HITACHI Ltd. 23 Aug., 1968 [1 Sept., 1967], No. 40397/68. Heading H3T. A bi-stable circuit comprises a pair of switching transistors coupled to a pair of control transistors which steer a common trigger pulse through one of two charge storage devices such that at the end of the pulse a switching action occurs. In Fig. I, if transistor T 1 is on and T 2 is off, the base current for T 1 is supplied via R 2 and the base-emitter path of T 4 . At this time transistor T 3 is biased off and hence on receipt of a pulse ei at P, diode D2 can pass current through T 4 , whereas D 1 is non-conducting. At the end of the pulse, a reverse current flows from T 4 through D 2 due to the minority charge storage effect. Thus the base current for T 1 is switched off, causing T 3 to be biased on and T 2 to be switched on. At the cessation of a second pulse, the bi-stable will revert to its original state. |
