Transistor

The transistor is a solid state semiconductor device which can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. It acts as a variable valve which, based on its input voltage, controls the current drawn by it from a connected voltage supply.

Packaging

Transistors come in many different chip carriers (see images), both through-hole (or leaded) such as metal canister and dual in-line package (DIP); and surface-mount, also known as surface mount device (SMD). The ball grid array (BGA) is the latest surface mount package (currently only for large transistor arrays and digital functions). It has solder 'balls' on the underside in place of leads. Because they are smaller and have shorter interconnections, SMDs have higher frequency characteristics but lower power rating.

Related Topics:
Chip carriers - Through-hole - DIP - SMD - BGA

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Often several package options are offered for a given transistor. Transistor arrays are sold in the same chip carriers as integrated circuits, often in DIP or SMD packages. A transistor array consists of multiple transistors built onto a single die for use as several individual transistors. Transistor packages are made of glass, metal, ceramic or plastic. The power rating and frequency of operation often dictates the type of packaging used. Power transistors have large packages that can be clamped to a heat sink for enhanced cooling. Additionally, most power transistors have the collector or drain physically connected to the metal can/metal plate. At the other size extreme, some surface-mount microwave transistors resemble grains of sand.

Related Topics:
Die - Heat sink

~ ~ ~ ~ ~ ~ ~ ~ ~ ~