Basic Electronics

Classification of resistors:

　　A can be classified by their manufacturing materials into—carbon film resistors, metal film resistors, wirewound resistors, and cement resistors, among others. Among these, carbon film resistors are the most commonly used, while cement resistors are often employed in high-power appliances or as load resistors.

　　B. Classified by power rating: ---- below 1/8W (chip), 1/8W, 1/4W, 1/2W, 1W, 2W, and so on

　　C. According to the resistance value notation, it can be further divided into —— digital notation and color-band notation.

　Units of resistance and their conversions:

　　The units of resistance are ohms (Ω), kiloohms (kΩ), and megaohms (MΩ), with the ohm (Ω) being the most fundamental unit of resistance.

　　Conversion of resistance units – 1 MΩ = kΩ = Ω

Identifying resistor values:

　　a. Digital Notation – This notation is commonly used in CHIP components. When identifying the value, the first two digits represent the significant figures, while the third digit indicates the multiplier.

　　b. Color code representation—The first and second bands indicate the significant digits, the third band represents the multiplier, and the fourth band denotes the tolerance.

2. Basic Electronics — Capacitors and inductors

　　Capacitance refers to the amount of electric charge stored for a given potential difference; it is denoted by the symbol C and measured in farads (F), the international unit. Capacitance is also commonly known as "capacitor." It’s a physical quantity that characterizes a capacitor's ability to store electric charge. Specifically, the capacitance of a capacitor is defined as the amount of charge required to increase the potential difference between its two plates by 1 volt. Capacitors are components designed to store electrical energy, enabling functions such as charging and discharging, filtering, coupling, and bypassing signals in electronic circuits.

　　Types – Capacitors can be classified into polar and non-polar types based on their polarity. Polar capacitors include aluminum electrolytic capacitors and tantalum electrolytic capacitors, while non-polar capacitors consist of ceramic capacitors and plastic capacitors.

　　An inductor is an electromagnetic induction component made by winding insulated wire—it’s also one of the commonly used components in electronic circuits. Essentially, an inductor consists of a series of coaxial coils wound tightly around an insulating core or magnetic/iron core using materials like enameled wire, silk-covered wire, or plastic-coated wire. In circuit diagrams, it’s represented by the letter “L.” Its primary functions include isolating or filtering AC signals, as well as forming resonant circuits when combined with capacitors and resistors.