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Trigger monostable trigger
The monostable flip-flop also consists of two inverters (Figure 3a). Compared with the bistable flip-flop shown in figure 1, the inverter 2 composed of transistor T2 is completely the same, but in the inverter 1 composed of transistor T 1, the resistor R1is replaced by a capacitor C, and R 12 is connected to Ec. In addition, the point b 1 of the T 1 tube is connected with a guide circuit consisting of D 1, R 1 and C 1, and the ui adds a trigger signal. The state voltage of the flip-flop is output by c 1 and c2.

The waveform of fig. 3b shows the working process of the monostable trigger. Before the arrival of external negative trigger pulse u (0 ~ t 1), the trigger is in a stable state. Since point b 1 is connected to voltage Ec through R 12, T 1 is turned on and T2 is turned off. The voltage uc 1 at point c 1 is low potential, the voltage u at point c2 is high potential, and the capacitor C is charged. At the moment of t=t 1, u comes, D 1 turns on through difference channel R 1C 1, b 1 is at a low potential, t 1 changes from on to off, uc 1. T2 is turned on, and uc2 drops to low potential. At this time, capacitor C forms a temporary stable state (T 1 ~ T2 period) through T2 discharge, which is called transient state. With the discharge of capacitor c, the potential at point b 1 rises. When t=T2, the potential of point b 1 turns on transistor T 1 again, and uc 1 drops to a low potential, while transistor T2 turns off and the potential of uc2 rises. During T2 ~ T3, due to the influence of Rc2C charging, uc2 rose slowly, forming a recovery period. Enter the original stable state after t3. Monostable flip-flops can be used for pulse shaping and pulse delay.

Various flip-flops can be composed of discrete components or can be realized by integrated circuits. However, with the development of integrated circuit technology, the types of integrated flip-flops are gradually increasing, with excellent performance and increasingly wide application. The basic trigger circuits are R-S trigger, T trigger, D trigger and J-K trigger.