What are semiconductors, what are diodes, what do they do?

When an electric current passes through various objects, different objects have different blocking abilities for the passage of the current, some objects can make the current pass smoothly, and some objects will not let it pass, or let it pass under a certain resistance. The ability of this different object to pass an electric current is called the conductivity of this object. All kinds of objects have different conductive properties, and all objects with good conductivity are called conductors.

Such as silver, copper, aluminum, lead, tin, iron, mercury, carbon and electrolyte are all good conductors. Conversely, objects that have a very poor ability to conduct electricity are called insulators. In addition, there are objects that have a less conductive ability than conductors, but are stronger than insulators, and such conductors are called semiconductors.

Such as commonly used transistor raw materials silicon, germanium, etc. Radios and CPUs are all semiconductors.

A diode is a one-way current that can be turned into a direct current.

Objects such as germanium, silicon, selenium, gallium arsenide, and many metal oxides and metal sulfides, whose conductivity is between conductors and insulators, are called semiconductors.

Semiconductors have some special properties. For example, the relationship between the resistivity and temperature of semiconductors can be used to make thermistors (thermistors) for automatic control; Its photosensitive characteristics can be used to make photosensitive elements for automatic control, such as photocells, photocells and photoresistors.

Semiconductors also have one of the most important properties, and if trace impurities are properly incorporated into pure semiconductor substances, their conductivity will increase millions of times. This characteristic can be used to manufacture a variety of semiconductor devices for different purposes, such as semiconductor diodes, transistors, etc.

When one side of a semiconductor is made into a p-type region and the other side is made into an n-type region, a thin layer with special properties is formed near the junction, which is generally called a p-n junction. The upper part of the figure shows the diffusion of carriers at the interface between p-type semiconductors and n-type semiconductors (indicated by black arrows). The middle part shows the formation process of the p-n junction, indicating that the diffusion of the carriers is greater than the drift (indicated by a blue arrow, and a red arrow indicates the direction of the built-in electric field).

The lower part is the formation of the PN junction. Represents the dynamic equilibrium of diffusion and drift.

The main characteristics of semiconductor diodes are doping, heat sensitivity, and light sensitivity.

1. Doping, when coal is mixed into the pure semiconductor, the conductivity of the conductor will be greatly enhanced. Diodes and transistors are made of semiconductors doped with impurities.

2. Thermal sensitivity, when the temperature rises, the conductivity of the conductor will be enhanced. This property allows certain semiconductors to be made into heat-sensitive devices.

3. Photosensitivity, when there is light irradiating the semiconductor, the conductivity of the semiconductor will also be significantly enhanced. This property allows some semiconductors to be made into photosensitive devices.

Diodes are one of the earliest semiconductor devices and are used in a wide range of applications. Especially in various electronic circuits, diodes and resistors, capacitors, inductors and other components are reasonably connected to form circuits with different functions, which can realize a variety of functions such as alternating current rectification, modulation signal detection, limiting and clamping, and voltage stabilization of power supply voltage.

Both semiconductor diodes and transistors are semiconductor transistor components. The basic principle is to use the unidirectional conduction function of the PN junction to work.

Semiconductor diodes are commonly used as rectifiers, switches, and detection components in circuits. Semiconductor transistors are commonly used as amplification, switching, oscillating elements in circuits.

Semiconductor diodes and transistors are semiconductor components and belong to active components.

Resistors, capacitors, and inductors are passive components.

Diodes and semiconductors are completely different things, and it can only be said that diodes are devices composed of semiconductors, and semiconductors can flow current in either direction.

The positive and negative terminals of the diode. The positive end A is called the anode, and the negative end K is called the cathode. The current can only move from the anode to the cathode.

Some beginners are prone to the misconception that half of semiconductors is half of half; Face diodes also have only half of the current flowing (which is wrong), and all diodes are semiconductors.

1. Unidirectional conductivity - rectification, detection and other characteristics;

2. Capacitance characteristics - barrier capacitance (affects frequency characteristics) and diffusion capacitance (affects speed characteristics);

3. Breakdown characteristics - Zener diode;

4. Reverse bias isolation feature - PN junction isolation.

Diodes are semiconductors. In fact, diodes and semiconductors are fundamentally different things. It can only be said that diodes are made of semiconductor materials.

made of an electronic device. Electric current can flow in any direction of the semiconductor. Diodes are one of the earliest semiconductor devices, and they are used in a wide range of applications.

The concept of semiconductors.

Semiconductors refer to materials with conductive properties between conductors and insulators at room temperature. Semiconductors in integrated circuits, consumer electronics.

Communication systems, photovoltaic power generation, lighting, high-power power conversion and other imitation fields have applications, such as diodes are devices made of semiconductors.

The concept of conductors.

Conductor refers to resistivity.

A substance that is very small and easily conducts electric current. The presence of a large number of freely moving charged particles in a conductor is called a carrier.

Under the action of the external electric field, the carriers move in a directional manner, forming an obvious current.

Diode applications.

Switching elements, rectifier diodes, limiting components, relay diodes, detection diodes, etc.

A transistor, also known as a bipolar transistor or transistor, is a semiconductor device that controls electric current. Its function is to amplify a weak signal into an electrical signal with a large amplitude value, and it is also used as a contactless switch. The three-grip pole tube is one of the basic components of semiconductors, which has the effect of current amplification and is the core component of electronic circuits.

The appearance and meta-segment symbols are shown in Fig.: