A resistor is a current limiting component that, when connected to a circuit, can limit the magnitude of the current passing through the branch it is connected to. The movement of an electric charge in an object will encounter a certain resistance, which is called a resistor. Components with a certain resistance value are called resistors. It is one of the essential and most commonly used electronic components in electronic products.

The function of a resistor:

The main function of resistors in circuits is to control the magnitude of voltage and current, and can also be combined with other components to form circuits with various functions such as coupling, filtering, feedback, compensation, etc. So, it is necessary for us to have a general understanding of the classification, main parameters, marking methods, and other basic knowledge of resistors.

Main performance parameters of resistors

1. Nominal value and allowable error: The country has established a series of resistance values as product standards, which are the nominal resistance values of resistors. The actual resistance value of a resistor cannot be exactly the same as its nominal value, and there is always a certain deviation between the two. The percentage obtained by dividing the maximum allowable error by the nominal value of the resistor is called the error of the resistor. For errors, the country has also established a series. The error of ordinary resistors can be divided into three types: ± 5%, ± 10%, and ± 20%, which are respectively represented by error levels I, II, and III on the markings. The resistance value marked next to the resistor in the circuit diagram is the nominal resistance value. When the resistance value calculated by the user during circuit design is not the nominal value, they can choose a nominal resistance value that is close to it.

2. Rated power: When current passes through a resistor, a certain amount of power is consumed, which becomes heat and raises the temperature of the resistor. In order to ensure the normal use of the resistor without being burned out, the maximum power it can withstand cannot exceed the specified limit. This maximum limit is called the rated power of the resistor. Generally, it can be divided into 1/8, 1/4, 1/2, 1, 2, 5, 10W. A resistor with a higher rated power has a larger volume. In circuits with lower current such as semiconductor radios, the rated power of the resistor is generally only 1/4W or 1/8W.

Resistors, abbreviated as resistors, are measured in ohms, represented by the Greek word "Ω". In practice, larger units such as K Ω and M Ω are commonly used. The conversion relationship between them is as follows: 1K Ω=1000 Ω, 1M Ω=1000K Ω.