Attenuators are devices that help in reducing the amplitude of a signal without disturbing its waveform. The attenuators are often made from resistors. The degree of attenuation may be fixed or variable (can be adjusted). Attenuators are used in communication devices and audio engineering. Attenuators can be classified into two types- The Optical fiber Attenuators which are used in systems where the optical power from a source is too high for the equipment in use. The work of the optical fiber attenuator is to reduce the power level to an acceptable level. And RF Attenuators which reduce the power level of the signal received by some amount with very little or no reflections.

A capacitor is often used to store electrical energy and discharge it when required. A capacitor is a simple device, which only stores electrons and does not produce them. Their main feature is that they deliver stable voltage for a number of functions like power conversion, DC-linking, frequency conversion, decoupling and filtering applications.The best quality of a capacitor is that it can discharge itself completely in fraction of seconds and can also absorb or eliminate ripples and spikes from a line carrying DC voltage. Capacitors are usually differentiated on the basis of materials they are made of like:

Ceramic Capacitors Electrolytic Capacitor

Film Capacitors

A coil can be defined as a conductor (or wire) that is rolled around a nonconductive material to form an inductor or electromagnet. A single loop of wire is often called a 'turn'. A coil is used for increasing the inductance in a wire. The more coils the wire has, the more inductance is produced in it. Coils are generally made up of rigid materials that can be given a spiral or helical shape. The most common materials used are copper wire or cable. Coils are generally differentiated on the basis of their usage like:

Armature Coils Choke Coils HVAC Coils Induction Coils

Relay Coils Solenoid Coils Transformer Coils Magnetic Coils

A fuse is defined as an over current protection device having a metallic wire or strip that melts when a large amount of current flows through it. The melting of the metal strip opens the circuit thereby saving it from excessive flow of current. Fuse is a very important part of power distribution system and it helps to prevent fire or damage, which generally occurs due to excessive heating of the wire. The speed of a normal fuse depends upon the quantity of current flowing through it. Fuses are usually differentiated as 'fast blow', 'slow blow' or 'time delay' on the basis of the time taken by them to respond to the flow of excessive current through them. The fuse selection depends upon the device for which it is being used. The various types of fuses are:

Blade Fuse Current Fuse Plug Fuse Thermal Fuse

Ceramic Fuse Glass Fuse Plastic Fuse Semiconductor Fuses

Inductors are passive electrical devices that are used in electrical circuits because they have the property of inductance. Inductance is the creation of a magnetic field that is created by changing the current running through a medium. Inductors are most commonly used in radio frequency devices and transformers. It can be termed as ideal when it offers zero electrical resistance to constant direct current. The different types of inductors based on their usage are:

Chokes Surface Mount Inductors

Through Hole Inductors

Passive devices that are used for providing definite amount of electrical resistance in circuits by limiting the flow of current or creating a drop in voltage between two points are known as resistors. Resistors are used in most of the electronic circuits and are based upon the Ohm's Law. The value of a resistor is calculated by a series of colored bands present on the surface of a resistor. Mostly there are four bands of color, the first two representing the base-value of resistance in two-digit number, the third indicating a multiplier and fourth stands for tolerance. Resistors requiring more precision have five bands, where the first three colors represent resistance in three-digit number and fourth and fifth lines representing multiplier and tolerance. Resistors are either classified on the basis of materials used or on the basis of their usage like:

Ceramic Resistors Film Based Resistors Metal Oxide resistors

Power Resistors Precision Resistors Surface Mount resistors