What is Passive Components for PCBA?

Abstract: Passive Components can refer to electronic components that consume but do not generate energy or electronic components that cannot generate a gain.


table of Contents

1. Introduction

2. Examples of passive components

3. Composite components or components composed of Passive Components

4. incremental passive

5. Other definitions of passive

6. Stability


Passive Components (Passive Components) is the name of certain PCB electronic components in Taiwan’s electronics industry, which is different from Active Components. In mainland China, they are called passive devices and active devices. At present, passive components (capacitors, resistors, inductances) and active components (integrated circuits) are also commonly used in China.


1. Introduction

If PCB electronic components work without any form of the power supply inside, then this kind of device is called a passive device.

In terms of circuit properties, passive devices have two basic characteristics:

1.1  It does not consume electric energy by itself or converts electric energy into other forms of energy.

1.2  It only needs to input signal, and it can normally work without an external power supply.

Passive Components: Relative to active components, it refers to circuit components that do not affect the basic characteristics of the signal but only allow the signal to pass without being changed. The most common ones are resistors, capacitors, inductors, ceramic oscillators, crystal oscillators, transformers, etc.

Active component: A component in a circuit component that can perform data calculation and processing. Including all kinds of chips, such as active crystals in semiconductor components, integrated circuits, image tubes, and displays, etc., are active components.

 Passive Components


2. Examples of passive components

2.1. Resistors

2.2. Capacitor

2.3. Inductors, including coils, reactors, chokes, etc.

2.4. Transformer: refers to the original and narrow transformer, that is, the traditional AC transformer. Excluding power adapters, power supplies are collectively referred to as transformers in a popular and broad sense.

2.5. Memristor, also known as a memristor

2.6. Quartz crystals, piezoelectric transistors or piezoelectric sheets, and filters made of them

2.7. Diodes are generally not classified as Passive Components, but due to the different definitions of passive components, under certain definitions, diodes are considered passive components.


3. Composite components or components composed of Passive Components

3.1. Passive filter is an electronic filter, which is completely composed of passive components.

3.2. The traditional quartz wireless receiver, an AM wireless receiver, does not require any power and is entirely composed of Passive Components.

3.3. Mineral radio.


4. incremental passive.

In-circuit design, informal passive components refer to components that cannot obtain power; this means that they cannot amplify the signal. Under this definition, passive PCB electronic components include capacitors, inductors, resistors, diodes, transformers, voltage sources, and current sources. They do not include devices such as transistors, vacuum tubes, relays, tunnel diodes, and glow tubes. Formally, for two-terminal components without memory, this means that the current-voltage characteristic is monotonically increasing. For this reason, control system and circuit network theorists refer to these devices as partially passive, incrementally passive, increasing, monotonically increasing, or monotonous. It is not clear how this definition can be formalized as a multi-port device with memory-in fact, circuit designers use this term informally, so it may not be necessary to formalize it [1].

The term is used colloquially in many other situations:

The passive USB to PS/2 adapter is composed of wires, resistors of PCB electronic components, and similar passives (in the sense of increment and thermodynamics). The active USB to PS/2 adapter contains the logic to convert the signal (valid in an incremental sense).

Passive mixers consist only of resistors (incremental passives), while active mixers include components that can gain (active).

In audio work, one can also find (increasing) passive and active converters between balanced and unbalanced lines. Passive balanced/non-planar converters are usually just transformers, and of course, there are necessary connectors, while active connectors are usually composed of differential drivers or instrumentation amplifiers.

 PCB electronic components

5. Other definitions of passive

In some very informal settings, passivity may refer to the simplicity of the device, although it is now almost universally believed that this definition is incorrect. Here, devices such as diodes are considered active, and only very simple devices such as capacitors, inductors, and resistors are considered passive. In some cases, the term “linear element” may be a more appropriate term than “passive device.” In other cases, “solid-state equipment” may be a more appropriate term than “active equipment.”


6. Stability

In most PCB electronic components, passivity can be used to prove that passive circuits are stable under certain standards. Note that this only works when using one of the above passive definitions-if the components in the two are mixed, the system may be unstable under any standard. In addition, passive circuits are not necessarily stable under all stability standards. For example, a resonant series LC circuit will have an unbounded voltage output for a bounded voltage input but will be stable in the Lyapunov sense, and a given bounded energy input will have abounded energy output.

Passive is often used in the control system to design a stable control system or display the stability of the control system. This is especially important in the design of large complex control systems (such as the stability of aircraft). Passivity is also used in certain areas of circuit design, especially filter design.


The above is the knowledge of Passive Components shared by the circuit board manufacturer Kingford.

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