The most basic electronic components: how much do you know about passive components?

Passive components are a kind of electronic components. Because there is no internal power supply in any form, the response to electrical signals is passive and obedient. They can only pass through electronic components according to the original basic characteristics, so they are also called passive components.


Inductance is an element that can convert electric energy into magnetic energy and store it. Its working principle is that when alternating current passes through the conductor, alternating magnetic flux will be generated in and around the conductor. Its main function is to isolate and filter the AC signal or form a resonant circuit with capacitors and resistors. Inductors are widely used in computer equipment, communication equipment, video and audio equipment, consumer electronics, electrical automation equipment, telecommunications and broadcasting equipment and other electronic products.
Inductance can be divided into self inductance and mutual inductance.

Self sensor

When a current passes through the coil, a magnetic field will be generated around the coil. When the current in the coil changes, the magnetic field around it also changes accordingly. The changed magnetic field can make the coil produce induced electromotive force (induced electromotive force) (electromotive force is used to represent the terminal voltage of the ideal power supply of the active element), which is self induction.
Electronic components, which are wound with wires and have a certain number of turns and can produce a certain amount of self inductance or mutual inductance, are often called inductive coils. In order to increase inductance, improve quality factor and reduce volume, iron core or magnetic core made of ferromagnetic material is often added. The basic parameters of inductor include inductance, quality factor, inherent capacitance, stability, passing current and service frequency. The inductor composed of a single coil is called self inductor, and its self inductance is also called self inductance coefficient.


When two inductance coils are close to each other, the magnetic field change of one inductance coil will affect the other inductance coil, which is mutual inductance. The size of mutual inductance depends on the degree of coupling between the self inductance of the inductance coil and the two inductance coils. The element made by using this principle is called mutual inductor.


Resistance refers to the two terminal electronic components made of resistance materials, with a certain structural form and can limit the passage of current in the circuit. Therefore, the resistance can be used as an electric heating element to convert electric energy into internal energy through the resistance between atoms to electrons. Resistors are mainly divided into fixed resistors, variable resistors and special resistors (mainly including sensitive resistors), of which fixed resistors are most widely used in electronic products.

Fixed resistance

There are many types of fixed resistors. The choice of which material and structure should be determined according to the specific requirements of the application circuit. Common wire wound resistors are often used in low-frequency circuits or as current limiting resistors, voltage dividing resistors, discharge resistors or bias resistors of high-power tubes. Wire wound resistors with high precision are mostly used in Fixed Attenuators, resistance boxes, computers and various precision electronic instruments.

Variable resistance

Variable resistance is also called adjustable resistance. The resistance value of adjustable resistance can be adjusted manually to meet the needs of the circuit. Adjustable resistance can be divided into many different models and types according to the size of resistance value, adjustment range, adjustment form, manufacturing process, manufacturing materials, volume, etc., including adjustable resistance of electronic components, adjustable resistance of porcelain disk, adjustable resistance of patch, adjustable resistance of wire winding, etc.

Special resistance

In short, special resistance is a special resistance different from ordinary resistance Thermistor, varistor, thermistor and safety resistor are special resistors.

Post time: Feb-11-2020