Classification and main characteristic parameters of resistors

Answer:
• Classification:
1. Wirewound resistors: general-purpose wirewound resistors, precision wirewound resistors, high-power wirewound resistors, high-frequency wirewound resistors.
2. Thin-film resistors: carbon film resistors, synthetic carbon film resistors, metal film resistors, metal oxide film resistors, chemical deposition film resistors, glass glaze film resistors, metal nitride film resistors. 3. Solid resistors
: inorganic synthetic solid carbon resistors, organic synthetic solid carbon resistors.
4. Sensitive resistors: varistors, thermistors, photoresistors, force-sensitive resistors, gas-sensitive resistors, and humidity-sensitive resistors.
• Main characteristic parameters:
1. Nominal resistance: the resistance indicated on the resistor.
2. Allowable error: The percentage of the difference between the nominal resistance and the actual resistance to the nominal resistance is called the resistance deviation, which indicates the accuracy of the resistor.
The corresponding relationship between the allowable error and the accuracy level is as follows: ±0.5%-0.05, ±1%-0.1 (or 00), ±2%-0.2 (or 0), ±5%-I level, ±10%-II level, ±20%-III level
3. Rated power: The maximum power allowed to be dissipated by the resistor for long-term operation under normal atmospheric pressure of 90-106.6KPa and ambient temperature of -55℃～+70℃.
The rated power series of wirewound resistors are (W): 1/20, 1/8, 1/4, 1/2, 1, 2, 4, 8, 10, 16, 25, 40, 50, 75, 100,
150, 250, 500. The rated power series of non-wirewound resistors are (W): 1/20, 1/8, 1/4, 1/2, 1, 2, 5, 10, 25, 50, 100.
4. Rated voltage: The voltage converted from the resistance value and the rated power.
5. Maximum operating voltage: the maximum continuous operating voltage allowed. When working at low pressure, the maximum operating voltage is lower.
6. Temperature coefficient: the relative change in resistance value caused by every 1°C change in temperature. The smaller the temperature coefficient, the better the stability of the resistor. The resistance value increases with the increase of temperature, which is a positive temperature coefficient, and vice versa.
7. Aging coefficient: the percentage of relative change in resistance value of a resistor under long-term load at rated power. It is a parameter indicating the life of the resistor.
8. Voltage coefficient: the relative change of the resistor for every 1 volt change in voltage within the specified voltage range.
9. Noise: an irregular voltage fluctuation generated in a resistor, including thermal noise and current noise. Thermal noise is due to the irregular free movement of electrons inside the conductor, which causes irregular changes in voltage between any two points of the conductor.