錦瑟‧李商隱
錦瑟無端五十弦，一弦一柱思華年。
莊生曉夢迷蝴蝶，望帝春心託杜鵑。
滄海月明珠有淚，藍田日暖玉生煙。
此情可待成追憶，只是當時已惘然。
白金西︰所謂明智，是能將事後之明﹐用於臨事之前。當真為『回反』者也。
─── 《M♪O 之學習筆記本《丑》控制︰【白金西】時回流反》
閱讀『美國線規』詞條有何樂趣耶？
American wire gauge
American wire gauge (AWG), also known as the Brown & Sharpe wire gauge, is a logarithmic stepped standardized wire gauge system used since 1857 predominantly in North America for the diameters of round, solid, nonferrous, electrically conducting wire. Dimensions of the wires are given in ASTM standard B 258.[1] The cross-sectional area of each gauge is an important factor for determining its current-carrying capacity.
Increasing gauge numbers denote decreasing wire diameters, which is similar to many other non-metric gauging systems such as British Standard Wire Gauge (SWG), but unlike IEC 60228, the metric wire-size standard used in most parts of the world. This gauge system originated in the number of drawing operations used to produce a given gauge of wire. Very fine wire (for example, 30 gauge) required more passes through the drawing dies than 0 gauge wire did. Manufacturers of wire formerly had proprietary wire gauge systems; the development of standardized wire gauges rationalized selection of wire for a particular purpose.
The AWG tables are for a single, solid, round conductor. The AWG of a stranded wire is determined by the cross-sectional area of the equivalent solid conductor. Because there are also small gaps between the strands, a stranded wire will always have a slightly larger overall diameter than a solid wire with the same AWG.
AWG is also commonly used to specify body piercing jewelry sizes (especially smaller sizes), even when the material is not metallic.[2]
或可拿來尋幽探秘乎？？
比方藉著 Tables of AWG wire sizes
Fusing current
索引，或能開拓視野，認識歷史裡人物事蹟也！
爾後面對『紅色條規』 Code Red 時︰
勿將電壓源短路。
將會反思鍊結『高溫、熔斷、火災、爆炸 …』吧！！
故知，雖曾有此
並聯電路
電池
假設一個電池組是以幾個單電池以並聯方式連接成電源，則此電源兩端的電壓等於每一個單電池兩端的電壓。例如，假設一個電池組內部含有四個單電池並聯在一起，它們共同給出1安培電流，則每一個單電池給出0.25安培電流。很多年前，並聯在一起的電池組時常會被使用為無線電接收機內部真空管燈絲的電源，但這種用法現在已不常見。
之用法，需得借『開關』避免
無『負載』時的內耗哩☺
那麼仔細衡量 
『範圍』及『安全顧慮』后，到底會不會定出
Where devices (for example, high-speed disk drives) require more power than a high-power device can draw,[45] they function erratically, if at all, from bus power of a single port. USB provides for these devices as being self-powered. However, such devices may come with a Y-shaped cable that has two USB plugs (one for power and data, the other for only power), so as to draw power as two devices.[46] Such a cable is non-standard, with the USB compliance specification stating that “use of a ‘Y’ cable (a cable with two A-plugs) is prohibited on any USB peripheral”, meaning that “if a USB peripheral requires more power than allowed by the USB specification to which it is designed, then it must be self-powered.”[47]
Mandate: Required
Effective Date: Now
The maximum current that any USB peripheral is permitted to draw from a standard USB 2.0 downstream port is 500mA. This includes USB 3.0 peripherals and peripherals that charge batteries from USB. For this discussion, a standard USB 2.0 downstream port complies with the definition of a host or a hub as defined solely in the “Universal Serial Bus Specification,” Revision 2.0 document.
The maximum current that a USB 3.0 peripheral may draw from a standard USB 3.0 downstream port is 900mA. USB 2.0 peripherals and USB 2.0 peripherals that charge batteries from USB are still limited to 500mA when attached to a standard USB 3.0 downstream port. For this discussion, a USB 3.0 standard downstream port complies with the definition of a host or a hub as defined solely in the “Universal Serial Bus 3.0 Specification,” Revision 1.0 document.
Use of a ‘Y’ cable (a cable with two A-plugs) is prohibited on any USB peripheral. If a USB peripheral requires more power than allowed by the USB specification to which it is designed, then it must be self-powered.
All upstream ports are required provide enumeration of USB functions.
必須如是的呢☆★