Transistors and Their Common Types

Transistors, originally known as “transit resistors” and “transfer resistors,” are components that have revolutionized the electronic world since their invention. As of the present, transistors serve as a staple of electronic circuitry, so much so that it is fairly unfathomable to have a PCB that is devoid of such elements. In this blog, we will discuss the characteristics, functionality, types, and applications of transistors, allowing you to better understand how the component has forever changed electronic design and manufacturing.

In their most basic form, transistors are simply semiconductor devices that may be used to either amplify or switch electrical signals and power. In their early days, many transistors were constructed with Germanium, that of which is sensitive to temperature. As such, manufacturers eventually switched to Silicon, enabling transistors to be constructed with lower costs while maintaining optimal characteristics. Generally, transistors have at least three terminals, allowing them to be connected to a circuit. At one terminal, a voltage or current is applied and allows for control through the other terminals. As the output controlled power of the transistor can be higher than the input control power, transistors are capable of acting as an amplifier.

Transistors often come in three main types, those of which are the point contact, Field Effect Transistor (FET), and Bipolar Junction Transistor (BJT). The point contact transistor served as the initial variation, those of which relied on Germanium for the construction of their semiconductor. Meanwhile, two Phosphor Bronze wires are passed through the component. With high current pulses, the Phosphorus could diffuse from wires into the semiconductor, forming P-type regions. With the formation of a PNP structure, negative resistance could be achieved.

FETs are transistors that exhibit a three terminal configuration that consists of the gate, source, and drain. As voltage controlled devices, the size and shape of their single channel can be managed. FETs can be further divided into two separate types which are the JFET and MOSFET. A JFET, or Junction Gate Field-Effect Transistor, is a three terminal device that is voltage controlled, meaning that it does not need biasing current to operate. As such, they serve as Depletion Mode components. MOSFET, or Metal Oxide Silicon Field Effect Transistor, components are unipolar. MOSFET components operate with two modes, those being Enhancement Mode and Depletion Mode.

The Bipolar Junction Transistor features three terminals which are the emitter, base, and collector. Current is used to control the transistors as a small current moving through the base will result in a large amount of current to flow from the emitter to the collector. BJTs are divided into two variations which are NPN and PNP types. The NPN transistor is a common BJT type that is composed of three layers. With this design, a P-layer is placed between two N-doped layers. With a PNP transistor, the opposite is seen as a single N-doped layer is placed between two P-doped layers.

Whether you find yourself in need of a BJT, FET, MOSFET, or another transistor type, look no further than NSN Parts Hub. As a leading distributor of transistors and related part types, we are well suited to fulfill all your operational needs with ease. Across our website, we list over 2 billion items that cater to a diverse set of industries and applications. Take the time to explore our offerings at your leisure, and our team is on standby to assist you throughout the purchasing process with rapid lead-times and competitive quotes for your comparisons. If you have any questions regarding our offered services or are ready to procure parts, call or email one of our representatives at your earliest convenience.