要了解晶体管的工作原理，您必须了解半导体如何对电位做出反应。一些半导体将是n型或负极，这意味着材料中的自由电子从负电极（例如，它所连接的电池）向正电极漂移。其他半导体将是p型，在这种情况下，电子填充原子电子壳中的“空穴”，这意味着它表现得好像正粒子从正电极移动到负电极。该类型由特定半导体材料的原子结构决定。现在，考虑一个npn晶体管。晶体管的每一端是n型半导体材料，并且它们之间是p型半导体材料。如果您将这样的设备插入电池，您将看到晶体管是如何工作的：连接到电池负极端的n型区域有助于将电子推进到中间的p型区域。连接到电池正极端的n型区域有助于减缓从p型区域出来的电子。中心的p型区域都有。通过改变每个区域的电位，您可以极大地影响晶体管上电子流的速率。
英国伯明翰大学Essay代写：什么是晶体管？
To understand how a transistor works, you have to understand how semiconductors react to an electric potential. Some semiconductors will be n-type, or negative, which means that free electrons in the material drift from a negative electrode (of, say, a battery it’s connected to) toward the positive. Other semiconductors will be p-type, in which case the electrons fill “holes” in the atomic electron shells, meaning that it behaves as if a positive particle is moving from the positive electrode to the negative electrode. The type is determined by the atomic structure of the specific semiconductor material.Now, consider an npn transistor. Each end of the transistor is an n-type semiconductor material and between them is a p-type semiconductor material. If you picture such a device plugged into a battery, you’ll see how the transistor works: the n-type region attached to the negative end of the battery helps propel electrons into the middle p-type region. the n-type region attached to the positive end of the battery helps slow electrons coming out of the p-type region. the p-type region in the center does both. By varying the potential in each region, then, you can drastically affect the rate of electron flow across the transistor.