Active component
From ArticleWorld
An active component is that component in an electronic circuit which provides gain in the form of power contribution. When referring to an alternating current circuit, an active component is that component of voltage, current or apparent power which adds power to the circuit. Such components are known as active voltage, active current or active power components.
In an electronic circuit, an active component changes the amplitude of a signal between the input and the output lines. Diminishing pulses from input lines can be boosted into new and more effective output pulses by regeneration with the help of an active component such as an active network hub. This is in contrast with a passive network hub, which simply a place of convergence for data arriving from directions, which is then forwarded out in other directions.
Contents |
Examples of active components
Some typical examples of active components used widely in electronics are described below:
Light emitting diodes
These are very useful in a wide range of applications as indicating devices. They are made from band gap semiconductors like gallium arsenide. Minority carriers cross the diode junction and emits photons when they combine with majority carries on the other side of the junction. Wavelengths ranging from the infrared to the ultraviolet region can be achieved from such diodes.
Thyristor
These are solid-state semiconductor devices with four alternating layers of n-type and p-type material. Thyristors conduct only when they receive a pulse of current at their gates. They conduct as long as they are forward biased. Thyristors find use in power electronics, where high currents and voltages are involved. They are invariably used to control alternating currents, where a polarity change in current is used to cause a device to switch off.
Field effect transistor
A field effect transistor (FET) is a transistor that makes use of electric fields to regulate the conductivity of the conducting channel present in its semiconductor material. The conducting channel is thus narrowed or broadened depending on whether electrical conductivity has to be boosted or restricted. FETs are the basis of modern-day digital integrated circuit technology.