1. Resistor
The physical components with resistance performance applied in electrical and electronic technology are called resistors, which are represented by the letter R.
Various types of resistors are widely used in electronic equipment. According to statistics, in general electronic products, resistors account for about 40% of the total number of components. Therefore, it is very important to master the basic characteristics of various resistors and use resistors correctly. They are used as voltage divider, shunt, current limiting resistor, circuit load, attenuation element in the circuit, RC loop element, etc.
2. Capacitance
Capacitor is an element composed of two metal plates with dielectric sandwiched between them, which is represented by the letter C.
Capacitor is one of the components widely used in electronic equipment. It has the ability to isolate DC and separate various frequencies. It is widely used in DC isolation, coupling, bypass, filtering, decoupling, phase shifting, resonant loop tuning, waveform conversion (differentiation, integration), energy conversion, time constant setting in control circuit, etc.
3. Inductance
The general inductor is formed by winding a certain number of turns (n) on the insulating tube with enamelled wire, gauze wrapped wire or silver plated copper wire, so it is also called inductive coil. The basic unit of inductance is Henry, which is represented by the letter "H".
Inductors can be used as tuning, filtering, blocking, notch, high frequency compensation, impedance matching, delay line, etc.
4. Relay
Relay is an automatic switch that uses low voltage and small current to control high voltage and large current. It plays the role of automatic operation, automatic regulation and safety protection in the circuit. The commonly used relays mainly include electromagnetic relay, dry spring relay, magnetic holding spring relay and solid-state relay. Among them, electromagnetic relay is a kind of relay which is widely used. It uses electromagnetic force to switch contacts. The character symbol of electromagnetic relay in the circuit is "K" or "Ka".
5. Semiconductor diode
The semiconductor diode is composed of a PN junction, two electrode leads and a shell package. The unidirectional conductivity of diode can be expressed by V-A characteristic curve. There are many kinds of semiconductor diodes, including germanium diodes, silicon diodes and gallium arsenide diodes; According to the structure, there are point contact diodes and surface contact diodes; According to the working principle, it is divided into tunnel diode, avalanche diode, varactor diode, etc; There are detection diodes, rectifier diodes, switching diodes and so on.
6. Crystal triode
Crystal triode, also known as semiconductor triode, is referred to as triode or transistor for short. It has three external electrodes (lead out pins), and some have four pins, of which one pin is grounded, which has nothing to do with the function of the other three poles. The basic function of triode is to amplify or switch the electrical signal. It is widely used in electronic circuits and is one of the core devices of electronic equipment.
7. Field effect transistor
When the electric field is applied to the surface of the semiconductor, the direction of the carrier and the direction of the hole can be changed by the electric field applied to the surface of the semiconductor, Or control the width of space charge region of PN junction, which is called semiconductor field effect.
The work of field effect transistor is based on the field effect of semiconductor surface.
8. Electroacoustic device
Electroacoustic devices are energy conversion elements that convert electrical signals into sound signals or sound signals into electrical signals. Commonly used electroacoustic devices in electronic circuits include speakers, microphones, headphones and buzzers.
Loudspeakers, commonly known as "loudspeakers", are used to convert electrical energy (electrical signal) into sound energy (audio signal) and radiate it. The character symbol of the loudspeaker in the circuit is "B" or "BL".
Microphone, commonly known as "microphone", is an acoustic electric converter that can convert sound signals into electrical signals, which acts on speakers. The text symbol of the microphone is "B" or "BM".
Headphones and buzzers are also electro acoustic energy conversion devices that convert electrical signals into acoustic signals.
9. Protective element
The protective elements used in electronic equipment include fuse resistor, ordinary fuse, thermal fuse and self recovery fuse. The protection element is generally connected in series in the circuit. In case of abnormal phenomena such as overcurrent, overvoltage or overheating in the circuit, it will fuse immediately to play a protective role, which can prevent the further expansion of the fault.
10. Quartz crystal resonator
Quartz crystal is generally used in electronic circuits to produce stable oscillation frequency and as crystal filter. Quartz crystal can be made into components alone, and can also form a quartz crystal oscillator together with semiconductor devices and resistance capacitance elements. Quartz crystal oscillator is a kind of anisotropic crystal. A slice cut from a crystal according to a certain azimuth is called a wafer (which can be square, rectangular or circular), and then a silver layer is coated on the two corresponding surfaces of the wafer and a pair of metal plates are installed to form a quartz crystal oscillator. The character symbol of quartz crystal resonator is B or BC.
