Power Transistors Overview

Transistor

Semiconductor device invented in 1947 for amplification.

Point-Contact Transistor

First type of transistor ever invented.

Bipolar Junction Transistor,

uses both electron and hole charge carriers.

Field effect transistor

controls current via electric field.

Emitter

Terminal that injects charge carriers into the base.

Base

Thin region that controls transistor operation.

Collector

Terminal that collects charge carriers from the base.

Power Transistor

Transistor designed to handle high power levels.

Cut-Off Region

Transistor state with no output current flow.

Active Region

Transistor state with current amplification occurring.

Quasi-Saturation Region

Transistor state with fast switching speeds.

Hard Saturation Region

Transistor state requiring time to switch states.

ICEO

Reverse leakage current when base is open.

V-I Characteristics

Graphical representation of output current versus voltage.

Voltage Gain

Ratio of output voltage to input voltage.

Current Density

Current per unit area in a device.

Forward Voltage

Voltage drop across the base-emitter junction.

Gain Bandwidth

Product of gain and bandwidth in a device.

Thermal Stability

Ability to maintain performance under temperature changes.

Switch-Mode Power Supplies

Power supply that converts electrical power efficiently.

Relays

Electromechanical switch controlled by an electric current.

Power Amplifiers

Amplifiers designed to drive loads with high power.

DC to AC Converters

Devices that convert direct current to alternating current.

Power Control Circuits

Circuits designed to manage electrical power flow.