可以說是最利用的電子元件，電阻得到很少沒有注意時相比，在設計中的其他組件。電阻是無源元件，可以減少電流和電壓，使設計者能夠實現對電路的控制。如果你在電子方面有任何背景，歐姆定律無疑被永久銘刻在你的腦海里。然而，公平地讓我們提供一點背景：

　　電阻的歐姆表示（Ω）是以喬治·西蒙·歐姆的名字命名的。歐姆等于一伏特（v）每安培（a）。歐姆定律決定了一個電阻的行為在一個理想的設置與公式：V = I *，其中V是電壓，我是電流和R是電阻。

　　本文的目的是給在Digi-Key電阻概述：我們的產品在我們的網站上有電阻，有顏色編碼操作的通孔電阻和電阻不符合常規的顏色代碼布局的一些變化。我們也將觸及一些情況下，可能使電阻難以讀取沒有使用工具。

　　Resistor families

　　Resistors are available in a multitude of packages， materials， and with a variety of features. Delving into each type of resistor and their intended application is beyond the scope of this article， however， I want to touch on some of the common types Digi-Key carries. Chassis mount resistors are the monsters of the resistor category. Typically these can have power ratings starting around 5 watts， with the highest power rating we currently stock being upwards of 2.5 kilowatts. As the name implies， chassis mount resistors are typically mounted to a chassis or heatsink to assist in heat transfer. Through-hole resistors can also fall in to a high power category based on the composition and package type. A common high-power package for through-hole resistors is the TO-247 package which lends itself to better heat dissipation. I would suggest reading our article on heat transfer for power resistors for more information. Within the through-hole family are the more common resistor types： axial leaded carbon film and metal film. They range typically from 1/8 watt up to a few watts， granted there are always exceptions. The chip resistor family includes resistors in the typical 0805， 0603 and 0402 packages， as well as a plethora of other physical sizes. Although there are a few higher power options in the chip resistor family， it is rare. They are typically utilized in mid- to low-power applications. Designs that use an array of resistors， typically with the same ohm value， can take advantage of resistor networks. Resistor networks combine two to upwards of twenty-eight resistors in one package; with the most common being four and eight resistors within the same package. Packages are available in chip， SIP （Single In-line Package） and DIP （Dual In-line Package） layout. On a side note： Digi-Key has an additional family within the resistor category that is for specialized resistors. These are typically temperature sensitive resistors focused on temperature compensation circuits.