Printed circuit boards (PCBs) are the building blocks of modern electronics. From your mobile phones to medical devices, these boards are everywhere. Have you ever wondered how PCBs power your device? Actually, at the heart of a PCB, several components work together to bring life to electronics. This complete guide on PCB components will walk you through each part.
Understanding those PCB parts is critical. WHY? Because each part plays a unique role in making a device function properly. Without their basic knowledge, you won’t be able to work with any device involving a PCB. Are you unfamiliar with PCB components? Worry not! This article will explain each part, its function, and specifications in simple terms. So, let’s begin!
Main Components of PCB
A PCB is made of several parts and components. Each of those parts performs a specific function to power the device. To truly understand the working of the PCB, you first have to understand its parts. So let’s dive in and explore standard PCB board parts and see how they contribute to the overall operation.
1- Resistors
A resistor is a small electronic component that controls or limits the flow of current. Actually, in PCB, not all parts need the same amount of electricity. Some parts are very sensitive and get damaged if too much current passes through them. That’s where the resistor comes into the scene. They protect those parts by slowing down the current to a safe level. Most resistors are tiny, cylindrical, with colored bands on them. These bands represent the resistance value, using a color code.
2- Capacitors
A capacitor is another PCB part that stores and releases electrical energy. Sometimes, the electricity doesn’t flow evenly. It may come in small surges or drops. So a capacitor smooths out the electrical flow by absorbing extra energy. It releases stored energy when needed. HOW? A capacitor is made of two metal plates with a dielectric material in between. When electricity flows into the capacitor, one plate stores positive charge and the other stores negative charge. The capacitor holds this charge until it’s needed.
3- Inductors
This part of the PCB stores energy in the magnetic field when current passes through it. By storing this energy, it resists changes in the flow of electricity. Let me explain how it works. Actually, an inductor is made by winding a copper wire into a coil. So, in case of current changes, i.e., increases or decreases, the inductor resists that change by creating a reverse voltage. In this way, this part stabilizes the current in a circuit, not by blocking it but by slowing it down.
4- Diodes
A diode is the PCB board part that acts like a one-way gate for electricity. It allows the electricity to flow only in a single direction and blocks it in the opposite direction. Diodes have two ends: anode( positive) and cathode (negative). Current can only flow when the positive voltage is applied to the anode and the negative to the cathode. When you reverse it, the diode stops the flow, acting like a closed gate. This property makes the diodes very useful for protecting circuits.
5- Transistors
The transistor is a tiny but powerful part of the PCB. It acts like a switch or an amplifier that can turn signals on and off or make weak signals stronger. Transistors basically consist of three legs. Those legs include:
- Base – It controls the transistor.
- Collector – This is where the current comes in.
- Emitter – This is where the current goes out.
When a small current enters the base, it opens the gate. This lets a larger current flow from the collector to the emitter. This is how it acts as a switch. At the same time, it can also boost the weak signals and act as an amplifier.
Quick Highlight: A Transistor comes in two main types, including:
- BJT (Bipolar Junction Transistor): Uses current to control current.
- MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor): Uses voltage to control current.
6- Integrated Circuits (ICs)
An integrated circuit (IC) works like a mini circuit. It holds many components, such as resistors, transistors, and diodes, all packed tightly into a single microchip. These IC board components work together to complete a complex task. ICs help make circuits smaller, faster, and more reliable. Before ICs, electronic devices used many separate components that took up a lot of space. However, now all those parts are combined into one single unit. They usually range from 8 pins to 100-plus pins.
7- Switches and Relays
Switches and relays are both control components of the PCB. They manage the flow of electricity in a circuit, but in a slightly different way. HOW? Switches are manual parts that allow you to open or close a circuit by hand. On a PCB, switches control whether current flows through a particular path.
On the flip side, relays are electrically operated switches. A user does not flip it on or off. Instead, a small electric current activates an internal coil, which opens or closes a circuit. Simply put, in relays, a low-power signal controls a high-power circuit. So they become more useful when you have control of large loads without directly touching them.
8- Connectors
Connectors are another critical component of the PCB that allows it to connect with other components or external boards. They make it possible to attach wires, cables, or other PCBs to a board. In simple words, connectors act as a bridge to transfer power or data from one place to another in a PCB. There are many types of connectors. Some of those are specific to just transferring data, while others are responsible for power transfer. The common ones include:
- Pin headers
- USB ports (for charging or data transfer)
- Audio jacks
9- Crystals and Oscillators
Crystals and oscillators help the PCB keep accurate timing. In simple words, they act as a clock, making sure everything runs in sync. A crystal is made of quartz. It vibrates at a precise frequency when electricity is applied to it. These vibrations generate a consistent pulse, similar to music. These pulses are what keep time or control the speed of operations in digital circuits.
On the other hand, oscillators produce a continuous electronic signal (waveform) at a specific frequency. These signals tell your device when to perform actions, such as displaying something. In this way, they help everything run in a proper rhythm. In other words, the oscillator produces the signal (the beat), and the crystal ensures the beat remains consistent.
10- Sensors
Sensors are the parts of a circuit board that detect changes in the environment. Once the sensor detects the change, it sends signals to the primary circuit and helps the device know what to do. They are placed directly on the PCB to interact with the surroundings. There are many types of sensors, such as light sensors, motion sensors, and temperature sensors. A good-quality PCB can support different sensors at once. This helps keep everything aligned and secure.
How Are PCB Components Placed?
Before making electronic devices, printed circuit board components must be carefully placed. The placement of these parts of a PCB is a critical step in the manufacturing process. It affects how well the circuit works and how long it lasts. Depending on the design and purpose, there are two main ways to mount parts on a circuit board. Let’s explain them simply.
1- Through-Hole Mounting
Through-hole mounting is one of the oldest ways of placing components on a PCB. Actually, in this method, each component has a metal lead or leg. Those legs are inserted into holes drilled through the PCB. Once you have pushed those leads to the hole, solder them on the opposite side of the board. Soldering is the process of joining two metal parts using a metal wire known as solder. This method creates a strong mechanical bond and makes it ideal for parts that might experience physical stress.
2- Surface Mount Technology (SMT)
SMT is the method of directly placing the components on the surface of a PCB. There is no need to drill the holes. In this technique, components do not have long leads. Instead, they contain small flat metal ends or leads that rest directly on the surface of the board. Once the ends are placed on the PCB surface, they are soldered using heat. This method is more efficient, faster, and allows a compact design. SMT also lets manufacturers add more components. This boosts the PCB’s capabilities for smart devices.
Key Considerations When Selecting PCB Board Components
When designing a PCB, choosing the right components is a critical step. The size, type, and cost of parts of the circuit board significantly impact how the final board performs. Feeling overwhelmed while choosing the PCB components? Worry not! Here are some key factors you must keep in mind.
- Focus on Size and Space: First of all, decide on the size of the PCB parts. Not all the circuit board electronic components are the same size. Some are small while others are big. So choose the component that fits your board size perfectly without crowding.
- Check Power and Voltage Ratings: Each of the circuit board parts has its own voltage and power limits. So make sure the component you choose can easily handle the amount of electricity your board will use. Therefore, always pick the part with the right rating of power and voltage to prevent any mishap.
- Thermal and Environmental Tolerance: If your PCB is used in hot areas, check its thermal tolerance. Make sure it has high thermal resistance so it can handle high heat in outdoor conditions.
- Choose Trusted Suppliers: Always get your PCB components from a trusted supplier. This reduces the risk of getting fake or low-quality parts. So I recommend choosing reliable PCB manufacturers in China. They offer both high-quality and complete production services at low cost.
- Think About Cost: Lastly, keep your budget in mind. However, remember that choosing the cheaper part of the PCB may save money initially, but it may cost more later. So a balance between quality and price helps keep your PCB assembly cost under control.
Frequently Asked Questions
Why are PCBs necessary in electronics?
PCBs are important because they hold and connect all the electronic components in an organized way. Moreover, instead of using messy wires, PCBs use copper paths to let electricity flow.
What materials are PCBs made from?
PCBs are made from a conductive base material and a thin layer of copper. The most common base material is FR-4. It is a strong, heat-resistant fiberglass epoxy. On top of this base, a thin layer of copper is added, which forms electrical pathways.
Can I recycle PCB components?
Yes, many PCB components can be recycled and reused. But it requires care and proper tools. Many electronic recycling companies extract valuable metals, such as gold, silver, and copper, from PCBs. However, recycling PCB parts at home is not possible. So it is better to sell those parts to recycling centers.
Conclusion
Printed Circuit Boards (PCBs) are the basis of nearly every electronic device. However, these boards do not work alone. Several components work together to power your device. In this article, I have explored those components and how they work. Some of them are active components that require power to operate, like transistors.
However, some components are passive, and they don’t need power to operate. Therefore, understanding their differences and functions is crucial to addressing any issue. Moreover, choosing the right part for your PCB is also key. For this purpose, you should consider size, space, cost, and a reliable supplier. Lastly, circuit board components identification is also essential.