Passive Components

A passive component is a module that does not require energy to operate, except for the available alternating current (AC) circuit that it is connected to. A passive module is not capable of power gain and is not a source of energy. A typical passive component would be: resistors, inductors, capacitors and transformers which together are required to build any electrical or electronic circuit.

Passive devices can be used individually or connected together within a circuit, either in a series or in a parallel combination to control complex circuits or signals.

Types of Passive Components

  • Capacitors

A capacitor is a component that can gather and hold a charge in a way that is similar to how a battery functions. The capacitor is made of 2 close conductors (usually plates) that are separated by a dielectric material. The plates accumulate electric charge when connected to power source. One plate accumulates positive charge and the other plate accumulates negative charge. It can hold the charge even when the voltage is no longer applied. Different types of capacitors are film capacitors, mica capacitors, ceramic capacitors, electrolytic capacitors, aluminium electrolytic capacitors, tantalum electrolytic capacitors and power factor correction capacitors

  • Resistors

A Resistor is an electrical device that resists the flow of electrical current. Although a resistor does not amplify or shape the electric current in any way its a powerful little device as it enables you to put the brakes on current flow in a very controlled way

  • Inductors

An inductor is a passive device that can store or deliver energy but cannot generate it. An ideal inductor is lossless, meaning that it can store energy indefinitely as no energy is lost as heat. Inductors are sometimes known as coils, chokes, electromagnets and solenoids

  • Ferrite Cores

A ferrite core is a ceramic compound that includes a mix of iron and another type of metal. Ferrite is common in many types of electrical components, including antennas. This magnetic core features wound components, such as windings from a transformer and inductors. It is useful because it offers low electrical conductivity along with high magnetic permeability.

  • Surge Protection Components

Surge protectors are a part of nearly every home and office today. They provide your expensive electronic devices with added protection against surges of electricity, which would ultimately destroy them.

Guides & Articles


In our comprehensive Capacitors Guide we look at MLCC's and the alternatives available


Everything you need to know about variable resistors

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