PCBs are packed with various electronic components, each playing a unique role. Understanding these parts makes it easier to grasp how circuits function, fix issues, and create your electronic projects.
Below, we explain some of the most common components you’ll come across and their role in a circuit.
1. Resistor
A resistor is a passive component that opposes the flow of current. It converts electrical energy into heat, and the resistance value is measured in Ohms (Ω).
Primary functions:
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Limiting current: Prevents damage to other components.
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Dividing voltage: Creates specific voltage levels within a circuit (e.g., in voltage divider networks).
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Biasing: Establishes specific operating conditions for active components like transistors.
2. Capacitor
A capacitor is a passive electronic component that stores electrical energy in an electric field. It is made up of two conductive plates separated by a dielectric material, and its ability to store charge is measured in farads (F).
Primary Functions:
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Filtering: Smooths out voltage fluctuations, such as in power supplies, to provide a steady output.
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Decoupling: Stabilizes power supply lines for integrated circuits (ICs) by offering local energy storage, preventing voltage drops.
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Coupling: Allows AC signals to pass through while blocking DC signals in a circuit.
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Timing: Works with resistors to create delays or oscillations in timing circuits, such as in clocks or oscillators.
3. Diode
A diode is a semiconductor device that acts as a one-way valve for current, allowing it to flow in only one direction (from anode to cathode). It is essential in various electronic circuits for controlling the direction of current.
The primary functions include:
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Rectification: Converts alternating current (AC) into pulsating direct current (DC), commonly used in power supplies.
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Reverse polarity protection: Prevents damage to a circuit if power is connected incorrectly by blocking reverse current.
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Voltage clamping/clipping: Limits voltage in circuits to protect components by clipping or clamping signals at a set level.
4. Inductor
An inductor is a passive electronic component that stores energy in a magnetic field when current flows through it. It fundamentally resists changes in current, making it a key element in managing electrical signals in circuits. The inductance of an inductor is measured in Henry (H).
Primary functions and applications:
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Filtering: Inductors are used in conjunction with capacitors to form filters (e.g., LC filters) that block or pass specific frequencies, ensuring clean signal processing in electronic devices.
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Energy Storage: Inductors are essential in switching power supplies, such as buck and boost converters, where they temporarily store energy for efficient power conversion.
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Resonant Circuits: When paired with capacitors, inductors form LC tanks that oscillate at specific frequencies, vital for frequency selection and generation in applications like radios.
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Chokes: They block high-frequency alternating current (AC) while allowing direct current (DC) or low-frequency AC to pass, commonly used in power supplies to reduce noise.
5. Transistor
A transistor is a semiconductor device that can function as either a switch or an amplifier. It is the fundamental building block of modern electronics, enabling the creation of complex circuits and systems.
Primary functions include:
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Switching in digital circuits: Transistors are used to create logic gates (AND, OR, NOT) and memory cells, turning current on or off to represent binary states.
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Amplifying signals in analog circuits: A small input current or voltage controls a much larger output, making transistors essential for audio amplifiers, radio frequency circuits, and more.
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Regulating voltage: Transistors stabilize output voltage in regulator circuits, ensuring consistent performance despite variations in input or load.
6. Integrated circuit (IC)
An IC is a miniaturized electronic circuit fabricated on a single semiconductor material (usually silicon). It integrates hundreds to billions of individual components (e.g, transistors, diodes) into a single, compact package.
Types of ICs include:
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Microprocessors
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Microcontrollers
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Memory chips
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Digital, analog, and ICs
7. Connector
A connector is a device that provides a detachable mechanical and electrical interface between different parts of an electronic system. It allows for easy connection and disconnection of cables, boards, or other electronic modules without permanent soldering.
Types of connectors and their application:
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Board-to-board connector: Used to connect multiple printed circuit boards (PCBs).
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Wire-to-board connector: Employed to connect individual wires to PCBs.
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Input/output (I/O) connector: Includes interfaces like USB, HDMI, Ethernet, D-sub, and audio jacks for communication and data exchange.
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Power connector: Suitable for power delivery, such as barrel jacks or AC inlets.
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RF connectors: Specialized connectors for high-frequency radio signals, e.g., SMA and BNC.
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Terminal blocks: Provide screw-down wire connections, commonly used in industrial applications.
Each of the components described above plays a vital role in enabling the functionality of electronic circuits. Whether in a simple power supply or a complex microprocessor system, these components form the foundational building blocks of modern electronics.