“555”电路是一种将模拟功能和逻辑功能集成在同一硅片上的混合集成电路,价格低廉,性能可靠。只要加以少量外接元件便可构成多种模拟或数字电路。本文介绍其在仪表中的各种应用:组成V/f变换器;简易逻辑判别;逻辑电平检测;升压稳压电路,电容微量变化测试;定时、长延时电路;廉价温度控制器;SCR高频触发电路;分频、倍频电路;线路通断测量仪;高压发生器及直流电压极性变换器等。 The 555 circuit is a hybrid integrated circuit that integrates analog and logic functions on the same silicon, offering low cost and reliable performance. As long as a small amount of external components can constitute a variety of analog or digital circuits. This article describes its various applications in the instrument: the composition of V / f converter; simple logic discrimination; logic level detection; step-up regulator circuit, the capacitance variation test; timing, long delay circuit; cheap temperature controller; SCR high-frequency trigger circuit; frequency, frequency multiplication circuit; circuit on-off measuring instrument; high voltage generator and DC voltage polarity converter.