原创献给555定时器的一首诗

 2018-8-27 11:02  3306 14 14 分类: 模拟

若你是一名电子工程师，有些数字会让你刻骨铭心，比如4004（世界上首款商用微处理器芯片）和8051（如果不是首款，那肯定是早期微控制器中最受欢迎之一）。

当然，还有一个让我们所有人都恋恋不忘的数字，那就是555。它是Signetics定时器集成电路（IC）命名所采用的数字，由Hans R. Camenzind于1971年设计并于1972年上市。它包括25个晶体管、两个二极管和15个电阻器，并利用到了一些巧妙的设计技术，例如用直接内部电阻来代替外部恒流源——Hans设法将此555塞入到8引脚的封装中。

第一代Signetics NE555（来源：Stefan506）

555有三种主要工作模式：单稳态（单次触发）、双稳态（施密特触发器）和无稳态（自激振荡）。555的多功能性，加上其低廉的价格、易用性和稳定性，使得很多人至今仍在使用它。多年来，电子爱好者和专业工程师们已经用这个“小滑头”开发了成千上万的应用。

我们中有许多人都对555有着浓厚的感情，其中有些人又比其他人更感兴趣。例如，我的朋友Daniel B. Levine（danielblevine.com）——EEWeb上“Raster Scam: An Unconventional History of Computer Graphics”一文的作者——就给我发了以下这首诗：

Ode to a 555 Timer (by Daniel B. Levine) （求大神翻译！）

Thou still unravish’d bride of analog design,
Thou foster-child of biplanar process and time,
Neither engineer nor poet escapes the seduction
Of the perfection of your monolithic construction.

You quicken the pulse, our composure you savage
When our gaze falls upon your eight-pin, dual inline package.
Or a milspec’d can, for space, sea or air,
Or the romantic 556—entwined as a loving pair.

Triple six may well be the mark of the beast,
But the angels beamed when the triple five was released.
You discharge to the world a positive supply
Of square waves as your output toggles twixt low and high.

Your fame unsurpassed, your reputation a tower,
There’s even a CMOS version for circuits with low power.
Though in this configuration noise is a struggle,
So always include a capacitor to decouple.

You switch without bounce, dividing a frequency,
Or modulating a pulse, all monostable-ly.
You compare with hysteresis, ignoring any hater
Jealous of your bistable multivibrator.

Your duty cycle’s variable, your comparator’s exacting,
Who knew astable oscillation could be so relaxing?
With every trigger we reset our faith anew,
And though you may flip-flop, we forever stay true.

You’re in every expert’s kit, and every student’s primer,
You stand, without peer, as the world’s favorite timer.
So say we all as long as engineering remains alive,
I think that I shall never spy a poem as lovely as a 555.