a. According to resistance characteristics

Fixed resistance, adjustable resistance, special resistance (sensitive resistance).

Those that cannot be adjusted are called fixed resistors, while those that can be adjusted are called adjustable resistors. Common ones, such as radio volume adjustment, are mainly used for voltage distribution, and we call them potentiometers.

b. According to the material of manufacture

Carbon film resistors, metal film resistors, wirewound resistors, Jabeson resistors, thin film resistors, etc.

C. According to the installation method

Plug-in resistors, chip resistors.

d. By function

Load resistance, sampling resistance, shunt resistance, protection resistance, etc. The main parameters of the resistance:

a. Nominal resistance value: The nominal resistance value on the resistor is called the nominal value. Units: Ω, kΩ, MΩ. The nominal value is marked according to the standard series formulated by the manufacturer, not arbitrarily calibrated by the manufacturer Yes, not all value resistors exist.

b. Allowable error: The maximum allowable deviation range of the actual resistance of the resistor to the nominal value is called the allowable error. Error code: F, G, J, K... (common error ranges are: 0.01%, 0.05 %, 0.1%, 0.5%, 0.25%, 1%, 2%, 5%, etc.).

c. Rated power: Refers to the allowable power consumption on the resistor under the condition of the specified ambient temperature, assuming that the surrounding air is not circulating, and the resistor is continuously operated for a long time without damage or basically without changing the performance of the resistor. Commonly there are 1/ 16W, 1/8W, 1/4W, 1/2W, 1W, 2W, 5W, 10W…

Marking method of resistance value and error

a. Direct marking method - the main parameters and technical performance of the resistor are directly marked on the resistor body with numbers or letters.

eg: 5.1k Ω 5% 5.1k Ω J

b. Text notation method - regular combination of text and numbers to represent the main parameters of the resistor:

eg: 0.1Ω=Ω1=0R1, 3.3Ω=3Ω3=3R3,3K3=3.3KΩ

c. Color coding method—color rings of different colors are used to represent the resistance value and error level of the resistor. Common resistors are generally represented by 4 rings, and precision resistors are represented by 5 rings.

d. Digital method

The nominal value of the component is expressed as a three-digit number. From left to right, the first two digits represent significant digits, and the third digit represents 10^n (n=0～8). It is a special case when n=9, which means 10^(-1).

The resistance value of 0-10 ohm with decimal point is expressed as XRX, RXX. eg:

471=470Ω 105=1M 2R2=2.2Ω

How to determine the color ring resistance ring

Please refer to the color code picture

a. Four-ring resistance:

Because the color ring that indicates the error is only gold or silver, the gold or silver ring in the color ring must be the fourth ring.

b. Five-ring resistance: This is a precision resistance.

(1) Judging from the resistance value range: Because the general resistance range is 0-10M, if the resistance value we read exceeds this range, it may be that the ring is wrongly selected.

(2) Judging from the color of the error ring: the colors of the color ring indicating the error are silver, gold, purple, blue, green, red and brown. If the color ring near the end of the resistor is not the error color, it can be determined as * **ring.