PCB Assembly

Different Kinds of Components Available in the Market

    Fig 1: Components Used In Electircal / Electronic Industry

    The electronics industry uses different components when manufacturing equipment and gadgets. Broadly, we may classify these components into three categories:

    • Structural Components
    • Electro-Mechanical Components
    • Electrical/Electronic Components

    Structural Components
    The industry uses these to form the inner assemblies and the outer structure, necessary for containing and holding other components that make up the equipment. Primarily made of metal and plastic, screws and adhesives hold these structures, while they perform the important functions of protecting the inner components from accidental movement and exposure to the elements. Sometimes, these components also serve as a shield for the user, protecting them from electrical shock.

    Electro-Mechanical Components
    These are components made up of electrical and mechanical sub-components, and perform their functions primarily with specific mechanical movements in the presence of electricity. Relays, Piezo products, Inductors, Transformers, Switches, Connectors, Displays, Printed Circuit Boards, Displays, and similar, fall under this category.

    Electrical/Electronic Components
    Components that function purely with electrical input and stimulus fall under this category. Primarily, there are two types of electronic components—active and passive—depending on how they transform the electrical input into their output. While the output provided by passive components is mostly a linear function of the input fed to them, active components may provide single or multiple outputs, with the output mostly bearing a non-linear relationship to the input.

    Fig 2: TH and SM Components

    There is yet another classification of electrical/electronic components—through-hole components and surface mount components (SMCs). While through-hole components are larger and have longer leads for soldering them on a PCB, SMCs are much smaller and have very small contacts. One advantage with SMCs is mounting them on the PCB does not require drilling the board as is necessary for inserting the leads of through-hole components—resulting in high component densities—an extremely desirable feature in the electronics industry.

    Fig 3: Comparison

    Passive Electrical/Electronic Components
    Some examples of passive components are:

    • Resistors
    • Capacitors
    • Sensors
    • Batteries

    Resistors : As the name suggests, resistors are passive components that oppose an electrical current flowing through them. Manufacturers fabricate resistors from different material to allow them to present a known amount of resistance, which they specify in Ohms.

    As resistors oppose the current flowing through them, the activity generates heat within the body of the resistor. Manufacturers also specify the wattage of a resistor as the amount of power the resistor can safely dissipate without burning out.

    Various types of resistors are available in the market for different applications. There are carbon resistors, metal film resistors, ceramic resistors, high-wattage resistors, and many more. Usually, the resistor body is too small to contain its printed value and tolerance figures on it. Manufacturers have circumvented the problem by printing a color code on the body of the resistor and thereby specify the value and tolerance of the resistor. Manufacturers offer resistors in through-hole as well as in surface mount packages.

    Capacitors : These components store electric charge. When connected in parallel to another component, capacitors act as reservoirs to reduce voltage dips across them. Connecting them in series within a circuit blocks the flow of DC current, while allowing AC current to flow through with a shift in the phase.

    Several types of capacitors, suitable for various applications, are available in the market and are known mainly by the dielectric material present within them. For instance, there are mica capacitors, polyester capacitors, paper capacitors, electrolytic capacitors, tantalum capacitors, and so on. Manufacturers specify the value of capacitors in F (Farads), and express it as nF or nano Farads, µF or micro Farads, and pF or pico Farads.

    A capacitor can withstand only a certain level of voltage before it is damaged, and the manufacturer specifies this. Therefore, when selecting a capacitor, one must take into consideration that it can withstand the voltage levels in the circuit. Manufacturers offer capacitors in both through-hole and surface mount packages.

    Sensors : These components sense, measure, and convert various physical parameters into electrical signal output. Sensors are available for measuring pressure, temperature, humidity, force, light flux, sound intensity, magnetic flux, and many more.

    Sensors are primarily analog devices, and depending on the design, their output is mostly a voltage proportional to the physical parameter it is sensing. They may include further electronics to process, amplify, or scale the output voltage to suit the specific application. The design may also include an analog to digital converter to convert the analog output voltage into digital form.

    Applications rarely use sensors in isolation, rather they are a part of a larger system that uses the information from the sensors to control the operation of the system. For instance, a controller takes input from a thermocouple measuring the temperature of water in a boiler and controls the power to the heater in the boiler to maintain the water temperature within a certain temperature range.

    Sensors are also available in several packages—through-hole, surface mount, and others. Depending on the type of the sensor and its application, manufacturers may make them in special packages as well. For instance, sensors for measuring force may resemble a thin membrane that the user must stick on the surface.

    Batteries : These are components meant to supply energy to the electronic circuits. Depending on the application, batteries may vary in capacity, chemistry, physical size, and terminal voltage. While some chemistries may allow repeated charging and discharging of the battery, others do not respond favorably to charging, and the battery needs a replacement on depletion.

    Active Electronic Components
    Manufacturers mostly make these components from different semiconductor materials, allowing them to operate in various ways. Some may need the presence of electricity to operate, while others can operate without any power input. Although many active electronic components are available in the market, it is possible to classify them broadly into a few broad categories, such as:

    • Diodes
    • Transistors
    • Integrated Circuits

    Diodes :These are semiconductor devices with a special PN junction to allow electric current to flow in one direction, while blocking it in the other. Available in both through-hole and surface mount variety, diodes are available for working from very low to extremely high frequencies. For instance, while rectifier diodes are suitable for operating at 50-200 Hz, Gunn diodes can operate at THz frequencies.

    Transistors : A large variety of transistors are available, ranging from miniature switching types for handling display pixels to high voltage, high power types suitable for operating large electric vehicles. Transistor technology also varies widely depending on the application, starting from simple bipolar types to MOSFET, JFET, HEXFET types, and many, many more. In the market, transistors are available in a large variety of packages, including through-hole types, surface mount types, and others.

    Integrated Circuits : As their name implies, integrated circuits are an integration of circuits comprising transistors and diodes. They are available to handle analog and digital signals, including converting analog signals to digital and vice versa. Manufacturers make ICs in various packages, including through-hole, surface mount, ball grid arrays, and many others. Micro-controllers, Microprocessors, and different types of memories fall under this category.

Wave Icon