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?qū)崿F(xiàn)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(chǎn)品在我們的網(wǎng)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(guī)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.