Introduction
Want to know what the 10 commonly used circuit board components in PCB Assembly are? Then read below, this guide will take you through the difference between active and passive components, and learn about the 10 most commonly used components. To help you implement your electronics projects.
Classification of Circuit Board Components
In learning about a circuit board, you must first learn how the components are grouped. We classify components based on what they do and how they work. This makes them easy to identify. The three main types are passive, active, and integrated circuits.
Passive Components
The simplest components on your PCB are the passive ones. They do not require an external power source to do their job. Instead, you apply them to control the flow of electricity by storing or releasing energy. You will be working with resistors, capacitors, and inductors as common examples.
Active Components
Active components require an external supply of power. You should think of them as workers on your circuit board. They apply power to increase or decrease signals and also serve as switches to regulate current. Two of the most common active components will be diodes and transistors.
Integrated Circuits
ICs (the integrated circuits, or powerful chips) consist of thousands or millions of small components. They serve as the brain of your device, being able to perform complex operations, such as data processing or memory storage. ICs are a fully integrated circuit system that fits in a single, tiny piece of silicon.
10 Commonly Used Circuit Board Components
Now, let’s look at some of the most commonly used components that you will have on your circuit boards.
Resistor
You apply a resistor to regulate the current in your circuit, and hence it is among the most frequently used components of the circuit board. Power circuits, signal processing, and amplifiers rely on it. Generally, on newer boards, you will be using what are called surface-mount (SMD) chip resistors. It has a value expressed in Ohms (Ω), and is written on schematics as R.
Resistors are categorized based on the way they perform:
- Fixed Resistors: Have one constant resistance value.
- Variable Resistors: Let you adjust the resistance level.
- Special Resistors: Change resistance based on heat or light.
Capacitors
A capacitor is an electronic component that can store electric charge at a specific voltage. The capability of storing energy is referred to as capacitance, and we express it in terms of Farads (F). You apply it to essential tasks such as filtering, coupling, bypassing, and tuning signals so as to enhance the stability. In these tasks, you will typically use ceramic and electrolytic capacitors on your PCB. They are labelled as C in circuit diagrams.
- Fixed Capacitors: Provide a single, stable capacitance.
- Variable Capacitors: Allow you to adjust or calibrate the capacitance.
- Polarized Capacitors: Must be installed in the correct direction.
Diode
A diode is a two-terminal component that functions as a one-way street for electricity. It is needed to change AC to DC and regulate voltage, as well as guard your circuit against power surges. On modern PCBs, you will usually use small, black surface-mount diodes. You use it in numerous tasks, including rectification, protection, and switching. A common and basic circuit board component in power management is a diode.
- Zener Diodes: They are used to regulate a certain voltage.
- LEDs (Light Emitting Diodes): They give out light when electricity flows through.
- Schottky Diodes: Suitable for high-speed switching.
- Photodiodes: Convert light into an electrical current.
Inductor
An inductor stores energy in a magnetic field when current flows through it. It typically consists of a conductive-wire coil. Its primary role is to resist current flow changes. This assists you in controlling the rate at which current increases or drops within a circuit. In filters and power supply circuits, inductors play an important role. Its capacity is measured in Henrys (H) and is labeled ‘L’ on schematics.
- Air-Core Inductors: Applied in cases where a small inductance is required.
- Ferromagnetic-Core Inductors: This has higher inductance values.
- Toroidal Inductors: They are outstanding in eliminating electromagnetic interference.
Transistor
A transistor is an electronic device made out of semiconductors, which is the foundation of modern electronics. It is able to amplify a poor signal to a stronger signal. It can also be used as a high-speed electronic switch to control current. You will find them in nearly all circuits, whether amplifiers or microprocessors. In your PCBA design, you will use it in amplification, oscillation, and switch circuits to achieve signal amplification, frequency conversion, and precise circuit control. This control is fundamental in computing and communications. Its small size and reliability make it an essential component.
- BJT (Bipolar Junction Transistor): A NPN and PNP bipolar (types of current-controlled devices).
- FET (Field-Effect Transistor): Is a voltage-controlled transistor (JFET type and MOSFET type).
Sensor
A sensor is a special device that is able to sense the physical inputs out there in the world. Light, heat, motion, or pressure are some of the inputs. The sensor then converts this physical input to an electrical signal. Your circuit could then read this signal to make a decision. With sensors, your projects can be interactive and cognitively aware.
- Proximity Sensor: This sensor identifies the surrounding objects without making physical contact. It prevents unintentional screen touches on devices like smartphones.
- Temperature Sensor: A temperature probe is a device that detects the levels of heat in its environment. You can find it in medical devices and home thermostats.
- Motion Sensor: This component observes physical movement in a particular space. It is widely applied in security systems and automatic lights.
- Pressure Sensor: A pressure sensor estimates the force exerted upon it. It is crucial information in automobile and aviation systems.
- Light Sensor: This sensor gauges the intensity of ambient light. It is used by your smartphone to turn its screen brighter or darker automatically.
Transformer
Another fundamental PCB component is transformers, which transfer electric power through circuits. You apply them to the conversion of voltage levels of the AC by electromagnetic induction. Transformers are components of power supplies and are commonly identified by the level of primary and secondary wire windings around a core. They make sure your components are powered at the correct voltage. Depending on your desired application, you could step up voltages or step down by adjusting. This is the reason why you find them in a power supply.
- Step-Up Transformers: Step up the voltage used on the input to the output.
- Step-Down Transformers: Reduce the number of voltages between the input and the output.
- Isolation Transformers: These are applied to isolate circuits in order to be safe.
Fuses
Consider a fuse as a safety conductor of your circuit board. It is a basic component that helps prevent damage to all the other components whenever there is an excess of electrical current. A fuse has a small wire that melts and separates the circuit when the current is too intense. This one item compromises itself to avoid the greater collapse of a system. You will often use small surface-mount or cartridge fuses on your PCB.
- Surface-Mount Fuses: These are small and found in large numbers on limited space board designs.
- Cartridge Fuses: Also known as Glass or ceramic tubes, cartridge fuses are frequently used in power supplies.
- Resetting Fuses (PPTC): Fuses that will automatically reset themselves when it is cooler.
Switches and Relays
Relays are like electrically operated switches to your PCB. They allow you to operate the control of a high-power circuit with a low-level signal of low power. There is an internal electromagnet that does the heavy work and physically closes the switch when you bring a small voltage to it. This is ideal to handle high-current components such as motors safely. Relays also assist you in isolating circuits from each other. They come in many different forms, anywhere between sliders, rotations, buttons, levers, toggles, and key switches.
- Pushbutton Switches: Turn a circuit ON when you press them.
- Toggle and Slide Switch: Maintain a fixed position (ON or OFF).
- DIP Switches: A block with a small number of switches that is used to configure a board.
- Relays: Use a low-power signal to control a high-power circuit.
Integrated Circuits (ICs)
An integrated circuit, or IC, is basically the brain of your electronic device. It carries thousands or even millions of tiny electronic parts in one compact chip. This enables you to design powerful circuits that are small, require less power, and are reliable. It is an essential component in your PCBA to carry out complicated functions. You apply it to digital signal processing, analog signal processing, and controlling communication interfaces. They are the very components that make modern electronic devices so smart.
- Microcontrollers (MCUs): An entire computer, built into one chip.
- Operational Amplifiers (Op-Amps): These are programmed to amplify analog signals.
- Logic Gates: Simple components of a digital circuit.
- Memory Chips: Store information in your system (e.g., RAM, Flash).
Comparing Component Types: Uses, Advantages, and Trade-offs
Now, we will compare the types of PCB components. All three types (passive, active, and electromechanical) have different purposes on your circuit board. It is important to learn their strengths and weaknesses. This information assists you in selecting the ideal electronic component for every task in your design.
Passive vs Active
When comparing passive and active circuit board components, you may think of them as simple and powerful. Passive components are strongly reliable and introduce zero noise, but cannot amplify signals. The active components provide the muscle and brain, allowing you to process and boost signals. You use passive parts for support and active parts for heavy lifting. This will determine the capability of your circuit.
Active vs Electromechanical (for switching)
When it comes to switching, it is a matter of either choosing speed or raw power. Transistors and other active switches are high-speed, and they can withstand frequent use. Electromechanical devices, such as relays, however, are well suited to safely handling high-voltage AC loads. You’ll use active switches in high-speed digital tasks. You choose relays as safe options to control powerful devices such as motors.
Integration and Size Considerations
Smart electronic components can save a lot of board space. An integrated circuit (IC) combines the functionality of numerous components in a small package. Surface mount components (SMD) enable dense designs to be made when placing parts. When you need parts to be stronger, such as connectors, a better mechanical bond of through-hole components will be desirable.
Cost and Availability
The PCB parts cost is also another factor you have to take into consideration. Passive components, such as resistors, are usually very cheap and readily available. Active components may be of low or high cost, from cheap diodes to costly microprocessors. Interestingly, electromechanical components such as high-quality connectors can become the most costly components on your board, so always budget accordingly.
How are Circuit Board Components Connected in a PCB?
A network of copper pathways or traces connects your PCB components. These traces are what you should think of as the highways of your circuit board. They transfer electrical power and electrical signals between all parts, allowing them to work together. You connect components to these traces either by soldering them on top (surface mount) or by inserting their leads through holes.
FAQs
What Is the Importance of Component Identification in Circuit Board Design?
It is essential to ensure that you have identified components accurately so that your design works. It allows you to select the correct components and to place them correctly on the board. Getting it right early eliminates design flaws and costly failures.
How Can I Identify Surface-Mount Components on a Circuit Board?
The surface-mount components are recognizable with reference to their package style and small codes printed on them. These components are extremely small, and therefore, you are likely to require a magnifier or a microscope to read the markings on them.
What Are Some Common Techniques for Identifying Passive Components?
Passive components are labeled and can be identified by reading the markings. Use color bands on resistors or the code numbers on capacitors. To be one hundred percent sure, these markings must always be cross-referenced with the official datasheet of the component.
How Can I Distinguish Between Different Types of Transistors?
Transistors can be distinguished by their package type and by the part number printed on them. Some transistors, such as BJTs and FETs, have different marking conventions; these markings indicate the specific purpose.
Conclusion
Now that you know how to recognize some of the more common circuit elements, resistors, capacitors, transistors, and ICs, you are in a great position to analyze practically any circuit board. This knowledge will be essential when it comes to designing a new product, debugging an issue, or when you are just wondering how your devices work.
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