While Electronic components process information in form of electrical signals, a Printed Circuit Board PCB is the skeletal structure on which the electronic components are mounted and soldered to hold them together and provide pathways for information to flow between components through PCB traces.
Some of the most commonly used electronic components are resistors, capacitors, inductors, diodes, LEDs, transistors, Crystals & Oscillators, Electromechanical components like relays & Switches, ICs, and connectors. These components have leads/terminals and are available in specific standardized packages that the designer can choose to suit his application. SMT (Surface Mount Technology) and Through-hole are the two types of mounting techniques used to place components on a PCB.
Resistors – Control Energy
Resistors are the foundations of current control—which is why they’re so often used in PCBs. These two-ended electrical pieces are fairly simple to understand and integrate into different projects. Resistance is often defined as the “ease” with which objects allow electricity to flow through them. Think of the difference between insulators and conductors; the former obviously possesses higher resistance than the latter.
Resistors, on the other hand, allow users to precisely define an object’s level of resistance. They are designed to resist the flow of an electric current by converting the electrical energy into heat—heat that is then dissipated. Resistors can be made of a wide range of materials and come in many different styles. The most common (and highly recommended for beginners) would be resistors made of carbon film in the axial style. Axial style resistors have leads on both ends of the rod. Their body is marked with different colored rings that represent the resistor’s resistance value.
Capacitors – Store Energy
Outnumbered only by resistors, capacitors are electronic components you’ll definitely find on every PCB board. Whereas resistors control an electric charge, capacitors temporarily store it. Think of them as tiny batteries with even tinier storage space. They are capable of losing and gaining full charge in a split second. Because of this, capacitors are commonly used for “filtering:” a process where a backup source of energy takes over when the main source of power drops in order to not lose or reset data.
In PCBs, capacitors electrostatically store energy to later release it to wherever power is needed in the circuit. It works by collecting opposing charges (positive and negative) on two conductive plates (typically metal) with some form of insulating material between them.
There are different types of capacitors, often categorized by the conductive material of the plates or the insulating material that separates them. Most beginners and casual hobbyists use polyester capacitors, ceramic capacitors, or radial capacitors. You’ll notice that some capacitors resemble resistors. The most telling difference is that resistors have leads on opposite ends. Capacitors have two leads protruding from the same side.
Transformers – Transfer Energy
General transformers transfer power from one source to another through a process called “induction.” PCB transformers function the same way. They transfer electrical energy from different circuits—and convert them—by increasing or decreasing the voltage. As with resistors, they technically regulate current. The biggest difference is that they provide more electrical isolation than controlled resistance by “transforming” the voltage.
PCB transformers consist of two or more separate inductive circuits (called windings) and a soft iron core. The primary winding is for the source circuit—or where the energy will come from—and the secondary winding is for the receiving circuit—where the energy is going to. Transformers break down large amounts of voltage into smaller, more manageable currents so as not to overload or overwork the equipment.
Transistors – Amplify Energy
Resistors may be fundamental to current control but transistors are fundamental to all modern electronics. They can, in fact, be considered the building blocks.
Contrary to storing, regulating, or controlling charges on the PCB, transistors amplify them. A bipolar transistor, which is the most common type of transistor, has three areas and three pins in which the current flows and is amplified. There are two types of bipolar transistors; NPN and PNP. Both are composed of the (1) base, (2) collector, and (3) emitter, and have both P-type areas and N-type areas.
NPN transistors are more commonly used than PNP transistors for a number of reasons. However, both have their advantages and disadvantages depending on the project.