论文部分内容阅读
(一)单次延时脉冲发生器要产生一个脉宽可变的延时脉冲,通常要用四个晶体管组成一对单稳态电路来实现.本电路(图1)仅用三个晶体管便可方便地实现延时和输出脉宽的调节.其工作原理如下:电路加正触发脉冲之前,BG_1截止,BG_2和BG_3导通.当正触发脉冲加入时,BG_1立即导通,电容器C_1两端已充电压便反向加在BG_2的基射极之间,使BG_2截止.然后C_1上电压通过BG_1、R_3和R_4放电,这便是暂稳态过程.一旦放电到BG_2的U??大于+0.7伏就使BG_2重新导通,BG_1重新截止.
(A) a single delay pulse generator to produce a variable pulse width delay, usually with four transistors to form a pair of monostable circuit to achieve this circuit (Figure 1) only three transistors Can be easily achieved delay and output pulse width adjustment.The working principle is as follows: Before the circuit is plus the trigger pulse, BG_1 end, BG_2 and BG_3 conduction.When the trigger pulse is added, BG_1 immediately turn on, both ends of the capacitor C_1 The charged voltage is reversely applied between the base emitters of BG_2, so that BG_2 is turned off, and then the voltage on C_1 is discharged through BG_1, R_3 and R_4, which is the transient steady state process.Once discharged to BG_2, U ?? is greater than + 0.7 volts BG2 re-conduction, BG_1 re-cut off.