1. Components: Products whose molecular components of raw materials are not changed by the factory during processing can be called components.

Components are devices that do not require energy. It includes: resistance, capacitance, and inductance. (Also known as Passive Components)

The components are divided into:

1). Circuit components: diodes, resistors, etc.

2). Connecting components: connectors, sockets, connecting cables, printed circuit boards (PCB)

2. Devices: The products whose molecular structure of raw materials are changed by the factory during production and processing are called devices. The devices are divided into:

1). Active device, its main characteristics are:

It consumes electric energy by itself

It needs external power supply.

2) . Discrete devices are divided into

bipolar transistors

field effect transistors


semiconductor resistors and capacitors.



The resistance is represented by "R" plus a number in the circuit, such as: R1 represents the resistance numbered 1. The main function of resistance in the circuit is: shunt, current limit, voltage division, bias, etc.


Capacitors are generally represented by "C" plus a number in the circuit (for example, C13 represents the capacitor numbered 13). A capacitor is a component composed of two metal films close together and separated by an insulating material. The characteristic of the capacitor is mainly to block the direct current and pass the alternating current.

The capacity of a capacitor indicates the amount of electric energy that can be stored. The obstructive effect of the capacitor on the AC signal is called capacitive reactance, which is related to the frequency and capacitance of the AC signal.

Crystal diode

Crystal diodes are often represented by "D" plus a number in the circuit, such as: D5 represents a diode numbered 5.

Function: The main characteristic of the diode is unidirectional conductivity, that is, under the action of forward voltage, the on-resistance is very small; and under the action of reverse voltage, the on-resistance is extremely large or infinite.

Because the diode has the above-mentioned characteristics, it is often used in circuits such as rectification, isolation, voltage stabilization, polarity protection, code control, frequency modulation, and noise suppression in cordless phones.


Although inductors are not used much in electronic production, they are equally important in circuits. We believe that inductors, like capacitors, are also an energy storage element, which can convert electrical energy into magnetic field energy and store energy in the magnetic field. The inductor is represented by the symbol L. Its basic unit is Henry (H), and millihenry (mH) is commonly used as the unit. It often works with capacitors to form LC filters, LC oscillators and so on. In addition, people also use the characteristics of inductance to manufacture choke coils, transformers, relays, etc.

Combination circuit

An integrated circuit is a device with a certain function formed by integrating transistors, resistors, capacitors and other components on a silicon substrate by using a special process. The English abbreviation is IC, also commonly known as a chip.

Analog integrated circuits refer to analog integrated circuits that are integrated with capacitors, resistors, transistors and other components to process analog signals. There are many analog integrated circuits, such as integrated operational amplifiers, comparators, logarithmic and exponential amplifiers, analog multipliers (dividers), phase-locked loops, power management chips, etc. The main components of analog integrated circuits are: amplifiers, filters, feedback circuits, reference source circuits, switched capacitor circuits, and so on. Analog integrated circuit design is mainly obtained through manual circuit debugging and simulation by experienced designers. Most of the corresponding digital integrated circuit design is automatically synthesized by using hardware description language under the control of EDA software.

Digital integrated circuits are digital logic circuits or systems made by integrating components and wiring on the same semiconductor chip. According to the number of gate circuits or components contained in digital integrated circuits, digital integrated circuits can be divided into small-scale integrated (SSI) circuits, medium-scale integrated (MSI) circuits, large-scale integrated (LSI) circuits, and very large-scale integrated (VLSI) circuits. ) Circuit and ultra large scale integration (ULSI) circuit. Small-scale integrated circuits contain less than 10 gates, or the number of components does not exceed 100; medium-scale integrated circuits contain between 10-100 gates, or the number of components is between 100-1000; The large-scale integrated circuit contains more than 100 gate circuits, or the number of components is between 10-10; the very large-scale integrated circuit contains more than 10,000 gate circuits, or the number of components is between 10-10; The number of components in a very large scale integrated circuit is between 10-10. It includes: basic logic gates, flip-flops, registers, decoders, drivers, counters, shaping circuits, programmable logic devices, microprocessors, microcontrollers, DSPs, etc