12 Commonly Used Components on PCBs for Beginners

Introduction

Printed Circuit Boards (PCBs) are the backbone of modern electronics. They contain various components that work together to create functional electronic devices. Understanding these components is essential for beginners in electronics and PCB design. This article covers 12 commonly used components on PCBs, their functions, and how they are used.

1. Resistors

Resistors limit or control the flow of electric current in a circuit. They are one of the most fundamental components on any PCB.

• Function: Reduce voltage, divide current, and control signal levels.
• Common Types: Fixed resistors, variable resistors (potentiometers), and thermistors.
• Unit: Ohm (Ω)

2. Capacitors

Capacitors store and release electrical energy. They are used for filtering, power stabilization, and timing applications.

• Function: Store charge, smooth voltage fluctuations, and filter signals.
• Common Types: Ceramic, electrolytic, tantalum, and film capacitors.
• Unit: Farad (F)

3. Inductors

Inductors are coils of wire that store energy in a magnetic field. They are mainly used in power supply circuits and signal processing.

• Function: Filter noise, store energy, and create oscillators.
• Common Types: Air-core, iron-core, and ferrite-core inductors.
• Unit: Henry (H)

4. Diodes

Diodes allow current to flow in one direction only, preventing reverse flow that can damage circuits.

• Function: Rectification, voltage regulation, and signal demodulation.
• Common Types: Rectifier diodes, Zener diodes, and Light Emitting Diodes (LEDs).
• Unit: Voltage drop (typically 0.7V for silicon diodes)

5. Transistors

Transistors act as switches and amplifiers in electronic circuits.

• Function: Amplify signals and control electronic switches.
• Common Types: Bipolar Junction Transistors (BJTs) and Field Effect Transistors (FETs).
• Unit: Gain (hFE for BJTs) and threshold voltage (Vth for FETs)

6. LEDs (Light Emitting Diodes)

LEDs are diodes that emit light when current flows through them.

• Function: Indicate status (power, connectivity, errors) or serve as a light source.
• Common Types: Standard LEDs, high-power LEDs, and RGB LEDs.
• Unit: Lumens (brightness)

7. Integrated Circuits (ICs)

ICs are compact semiconductor chips that contain multiple electronic components such as transistors, resistors, and capacitors.

• Function: Perform complex functions such as signal processing, power management, and computation.
• Common Types: Microcontrollers, operational amplifiers, memory chips.
• Unit: Varies based on type (clock speed for processors, storage capacity for memory chips)

8. Switches

Switches control the flow of electricity by opening or closing a circuit.

• Function: Manually or electronically control circuit connections.
• Common Types: Toggle switches, push-button switches, rotary switches.
• Unit: Resistance (Ohms when open = infinite, closed = near zero)

9. Connectors

Connectors are used to join different sections of a circuit or attach external components.

• Function: Provide electrical connections between different parts of a PCB or external devices.
• Common Types: Pin headers, USB connectors, audio jacks, power jacks.
• Unit: Contact resistance (measured in milliohms, mΩ)

10. Crystal Oscillators

Crystal oscillators generate a stable clock signal for timing and synchronization in circuits.

• Function: Provide precise timing for microcontrollers, processors, and communication modules.
• Common Types: Quartz crystal oscillators, MEMS oscillators.
• Unit: Frequency (Hertz, Hz)

11. Relays

Relays are electrically controlled switches that allow a low-power circuit to control a high-power circuit.

• Function: Isolate and control high voltage/current applications.
• Common Types: Electromechanical relays, solid-state relays.
• Unit: Coil voltage (V), contact current rating (A)

12. Sensors

Sensors detect environmental changes and convert them into electrical signals.

• Function: Measure parameters such as temperature, humidity, pressure, and motion.
• Common Types: Temperature sensors, motion sensors, light sensors.
• Unit: Varies by type (°C for temperature, lux for light, etc.)

Conclusion

These 12 components form the foundation of PCB design and electronics. Understanding their roles and applications is essential for beginners looking to build and troubleshoot electronic circuits. As you advance, learning how these components interact in complex circuits will be crucial for designing and optimizing electronic systems.