Release time：2024年4月25日
Author：Kama
A circuit board is a board with small electronic components such as resistors, capacitors, diodes, and transistors. It is also referred to as a printed circuit board (PCB).
The small electronic components are called circuit board components, and they are used to create electronic systems by placing them on the circuit board. Circuit board components are divided into three categories: basic components, power components, and mechanical components.
In electronic circuit boards, components can be broadly categorized into passive components and active components. Resistors, capacitors, and inductors are passive components. Passive components are electronic elements that can operate without needing a power source. They are termed "passive" because they cannot amplify or switch signals. Transistors, diodes, and integrated circuits (ICs) are active components. Active components require a power source to operate. They are termed "active" because they possess the ability to amplify or switch signals.
Additionally, there are other less conspicuous categories of elements present in PCBs. For instance, connectors are used to establish electrical connections between the circuit board and external sources. All these components together form a complete circuit.
Resistance Value: The resistance value of a resistor is an important factor to consider when selecting passive components. This value determines how much current can flow through the circuit, thereby influencing the overall perform
Tolerance: Tolerance refers to the range of values within which a resistor can have and still be considered effective. A lower tolerance value indicates a more precise resistor, which is crucial for circuits that require high precision.
Rated Power: The rated power of a resistor tells us how much power it can withstand before overheating or damage occurs. Selecting resistors with sufficiently high-rated power is essential to ensure the circuit can operate for extended periods without components being damaged. mance of the circuit.
Capacitance Value: The capacitance value of a capacitor is a critical factor to consider when selecting passive components. It determines how much charge the capacitor can store and affects the overall performance of the circuit.
Rated Voltage: The rated voltage of a capacitor determines the maximum voltage it can withstand without breakdown. Choosing capacitors with sufficiently high rated voltage is essential to prevent component failure and ensure the long-term reliability of the circuit.
Purpose: The first consideration is the purpose of the circuit board and the function the active component will perform. Different types of active components are suitable for various purposes, such as amplification, rectification, and signal processing.
Power Requirements: The power requirements of the circuit board will determine the type of active components needed. High-power circuits require active components with higher-rated power, while low-power circuits can use smaller components.
Rated Voltage: The active components' rated voltage must suit the circuit board's voltage range. If the rated voltage is too low, the component may malfunction and damage the circuit board.
Temperature Range: Active components generate heat during operation, so it's crucial to select components with temperature ratings compatible with the operating temperature range of the circuit board.
Speed Requirements: The speed requirements of the circuit board will determine the type of active components needed. High-speed circuits will require active components with higher operating frequencies and faster response times.
Size and Packaging: The physical size and packaging of active components will determine how they are mounted on the circuit board. The packaging type must be compatible with the layout and design of the circuit board.
Reference designators are a set of alphanumeric codes used to identify specific components on a PCB (Printed Circuit Board).
Resistor reference designators start with "R," capacitors start with "C," inductors start with "L," relays start with "K," transistors start with "Q," and so on. The letter is typically followed by a number, aiding in easily identifying components within similar groups. Common reference designators are as follows:
| Reference Designator | Component |
| A | Sub-assembly |
| C | Capacitor |
| D | Diode |
| F | Fuse |
| FB | Ferrite bead |
| FC | Filter |
| J | Jack connector |
| K | Relay |
| L | Inductor |
| M | Motor |
| P | Plug |
| PS | Power supply |
| Q | Transistor |
| R | Resistor |
| S | Switch |
| T | Transformer |
| TP | Test point |
| U | Integrated circuit |
| Y | Crystal for oscillator |
| Z | Zener diode |
In components like SOC ICs or QFP packages, the orientation of the component is crucial during the installation process. For such components, specifying the first pin by pin 1 numbering or a solid dot aids in easier installation or assembly. Pin 1 numbering or a dot helps you quickly identify and pick the IC for assembly on the PCB, understanding the starting position of the first pin.
The size and shape of components have a significant impact on the final dimensions of the circuit board. Smaller components enable more compact circuit board designs, which is particularly important in space-constrained applications such as wearable technology or small IoT devices. However, smaller components may be more challenging to work with during assembly, and their rated power may also be lower or more expensive.
When selecting components for a circuit board, it is crucial to choose components that can handle the required power and voltage levels. Components that cannot handle the necessary power may overheat or fail, leading to circuit malfunctions or even damage to the circuit board. Similarly, choosing components with insufficient voltage ratings may result in electrical breakdown or other failures.
The temperature range of components is another key factor to consider. Some components can only operate within a narrow temperature range, while others can handle a wider range. Choosing components that can withstand the expected extreme temperatures of the circuit board's intended application is crucial for ensuring the reliability of the circuit board.
Choosing robust and reliable circuit board components is crucial, especially when the circuit board requires frequent use or operates in harsh conditions. Opting for reputable brands with a track record of producing high-quality parts ensures that the circuit board operates normally within its expected lifespan.
Cost of circuit board components
Cost is significant when manufacturing circuit boards. It's essential to choose affordable parts that fit within the budget. However, keep in mind that cheaper parts may not always be the best option. They might not last long or function correctly. It's better to spend more money on high-quality components to ensure the circuit board operates correctly and has a longer lifespan.
Performance
The performance of components should meet the requirements of the final product. Designers should select components that can deliver the functionality, speed, and precision required for the application.