基于Proteus的555级联电路的仿真及频率计算

分析了救护车报警电路和555定时器的工作原理,用Proteus组合555芯片、电阻、电容对救护车报警电路进行了仿真,并将其仿真波形在同一屏幕上呈现出来,计算了其频率,计算结果与仿真结果一致.

一种基于555时基电路的振荡器设计

介绍555集成定时器内部各部分电路的构成和简单的工作原理,给出了相关参数说明,工作电压大小和构成电路的方法。进一步阐述了555定时器系统的功能以及各部分电路工作状态,并根据555定时器电路特点设计构成常见常用的振荡电路。给出设计方法,设计逻辑电路图。

Development of timer based on liquid level measurement system

This paper describes the design and development of the timer based on liquid level measurement system in which timer 555 is used in astable mode. The capacitor charging time i. e. the ON time pulse width of the timer output waveform which is measured using a digital storage oscillator （DSO）,is linearly proportional to the capacitance of a co-axial cylindrical capacitive transducer, and this capacitance once again linearly varies with the change in liquid level. Hence, we obtain a linear relationship between the liquid level and the capacitor charging time. The main advantages of this developed system are linear input-output relationship, small in size, easily portable, cost effective, and independent on the ambient temperature effect. The system can also be exploited to measure dielectric constant of liquid or solid in various process industries.

多功能电子钟的设计与搭建（英文）

这篇文章旨在记录一个电子钟项目的完成过程。这个项目的目标是建造一个搭建在面包板上的电子钟的电路使其能用两个计时器来准确计时1分钟。项目的最终成果是这个电子钟成功包含了3个计时器以及一系列附加功能,比如蜂鸣器、计时速度改变功能,以及计时重置功能。这些功能都用软件模拟成功并且搭建成功了。主要器件有74160,7447等集成电路模块。未来的提高方向是改良电子钟的外观和合理实用性。