在要求消除开关抖动的场合中,设计人员经常使用一个单刀双掷(spdt)开关来完成单刀单掷开关(spst)的功能。图中给出单一的施密特触发反相器电路,可以对单刀单掷开关去抖动。 TTL反相器(74LS14)内部有一16KΩ的工作电阻,当开关断开时,该电阻使门输入为高。一旦闭合开关,4.7μF的电容在第一次闭合时放电,内部电阻限制了电容的再次充电速度;这样有效地防止开关再次接触前的不希望的门 In applications that require the elimination of switching jitter, designers often use a single-pole double-throw (spdt) switch to accomplish the SPST function. The figure shows a single Schmitt trigger inverter circuit that can be debounced to the SPST switch. The TTL inverter (74LS14) has a 16KΩ internal resistor, which makes the gate high when the switch is off. Once the switch is closed, the 4.7μF capacitor will discharge on first closure, and the internal resistance will limit the rate at which the capacitor can be recharged; this effectively prevents unwanted doors before the switch touches again