1. Resistors
A physical component with resistance properties used in electrical and electronic technology is called a resistor, 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. It can be seen that it is crucial to master the basic characteristics of various resistors and use resistors correctly. They are used as voltage dividers, current dividers, current limiting resistors, circuit loads, attenuation elements in circuits, RC type loop elements, etc.
2. Capacitors
Capacitors are components composed of two metal plates with a dielectric in the middle, represented by the letter C.
Capacitors are one of the components used in large quantities in electronic equipment. They have the ability to isolate DC and separate various frequencies. They are widely used in DC isolation, coupling, bypassing, filtering, decoupling, phase shifting, resonant circuit tuning, waveform transformation (differentiation, integration), energy conversion, and time constant setting in control circuits.
3. Inductor
General inductors are made of enameled wire, yarn-covered wire or silver-plated copper wire wound on an insulating tube for a certain number of turns (N), so they are also called inductor coils. The basic unit of inductance is Henry (abbreviated as Henry), represented by the letter "H".
Inductors can be used for tuning, filtering, current blocking, notching, high-frequency compensation, impedance matching, delay lines, etc.
4. Relay
A 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 adjustment, and safety protection in the circuit. Commonly used relays mainly include electromagnetic relays, reed relays, magnetic latching reed relays and solid-state relays. Among them, electromagnetic relays are the most commonly used type, which uses electromagnetic force to switch contacts. The text symbol of electromagnetic relays in the circuit is "K" or "KA".
5. Semiconductor diode
A semiconductor diode is composed of a PN junction welded with two electrode leads, plus a shell package. The unidirectional conductive characteristics of the diode can be represented by the volt-ampere characteristic curve. There are many types of semiconductor diodes. According to the material, there are germanium diodes, silicon diodes and gallium arsenide diodes, etc.; according to the structure, there are point contact diodes and surface contact diodes; according to the working principle, there are tunnel diodes, avalanche diodes, varactor diodes, etc.; according to the purpose, there are detector diodes, rectifier diodes, switching diodes, etc.
6. Crystal triode
Crystal triode is also called semiconductor triode, abbreviated as triode or transistor, with three external electrodes (lead pins), some of which have 4 pins, one of which is grounded and has nothing to do with the functions of the other three poles. The basic function of the triode is to amplify the electrical signal or switch the electrical signal. It is widely used in electronic circuits and is one of the core components of electronic equipment.
7. Field Effect Transistor
When an electric field is applied in the vertical direction of the semiconductor surface, electrons and holes move under the action of the surface electric field, and the carriers are redistributed on the semiconductor surface. Therefore, the conductivity of the semiconductor surface changes under the action of the electric field, that is, changing the magnitude and direction of the applied voltage can control the concentration and type of carriers in the semiconductor surface layer, or control the width of the PN junction space charge region. This phenomenon is called the field effect of the semiconductor.
The operation of the field effect transistor is based on the field effect on the semiconductor surface.
8. Electroacoustic Devices
Electroacoustic devices are transducers that convert electrical signals into sound signals or convert sound signals into electrical signals. Commonly used electroacoustic devices in electronic circuits include speakers, microphones, headphones and buzzers.
Speakers are commonly known as "horns". Their function is to convert electrical energy (electrical signals) into sound energy (audio signals) and radiate them. The text symbol of the speaker in the circuit is "B" or "BL".
Microphones are commonly known as "microphones". They are a kind of sound-to-electric conversion device that can convert sound signals into electrical signals. Their function is opposite to that of speakers. The symbol for microphone is "B" or "BM".
Headphones and buzzers are also electro-acoustic transducers that convert electrical signals into acoustic signals.
9. Protection elements
Protection elements used in electronic equipment include fuse resistors, ordinary fuses, thermal fuses and self-recovery fuses. Protection elements are generally connected in series in the circuit. When abnormal phenomena such as overcurrent, overvoltage or overheating occur in the circuit, they will immediately fuse and play a protective role to prevent the fault from further expanding.
10. Quartz crystal resonator
Quartz crystals are generally used to generate stable oscillation frequencies and act as crystal filters in electronic circuits. Quartz crystals can be made into components for use alone, or they can be combined with semiconductor devices and resistors and capacitors to form quartz crystal oscillators. Quartz crystal oscillators are anisotropic crystals. Thin slices cut from a crystal at a certain azimuth angle are called wafers (which can be square, rectangular or circular, etc.), and then a silver layer is applied to the two corresponding surfaces of the wafer and a pair of metal plates are installed to form a quartz crystal oscillator. The letter symbol of quartz crystal resonator is B or BC.