Classification of resistors

Resistors used in the manufacture of PCB electronics are typically solid resistors, thin film resistors, and wirewound resistors. Ordinary fixed resistors have only two pins, and the pins have no positive or negative polarity. The two pins of the fixed resistor used in THT generally extend in the axial direction, and the pins are usually need to shaped before using. In order to be soldered and mounted on the board, and its resistance can be identified in the component body through the color ring. The chip resistor used for SMT assembly is as large as a rice grain, flat, with characters on the top indicating the resistance value of the resistor.

Resistors are classified into many types due to their different manufacturing methods, but the common resistors are as follows.

1.Solid core resistor

The solid core resistor is made of carbon mixed with a poor conductive material and added with a binder. According to different adhesives, they are divided into organic solid resistors and inorganic solid resistors, which are marked with the symbols RS and RN respectively. Such resistors are low in cost, inexpensive, and highly reliable, but have large resistance errors and poor stability.

2, Carbon film resistor carbon film

Carbon film resistors are made by evaporation of carbon or some alloys on the surface of a ceramic tube (rod), which is the most commonly used resistor in electronics. The carbon film resistor type has the RT mark (the small carbon film resistor is labeled RTX), which is inexpensive and has good voltage stability, but allows for a lower rated power.

3, Metal film resistor

The metal film resistor type has the RJ mark, and the surface is often painted with red or brown paint. It has high precision and good thermal stability. At the same rated power, the volume is only half of the carbon film resistor.

4, Wirewound resistor

The wirewound resistor has the RX mark in the model. It is made of nickel-chromium or manganese-copper alloy wire wound on the insulating bracket. The surface is often coated with insulating varnish or heat-resistant glaze. The wirewound resistor is characterized by precision. High, can withstand higher power, good thermal stability: the disadvantage is that the price is expensive, it is not easy to get high resistance.

5. Cement resistance

The cement resistor is wound around the non-alkaline heat-resistant porcelain, and is protected and fixed with heat-resistant, moisture-resistant and corrosion-resistant materials. The wire-wound resistor is placed in a square porcelain frame with special non-combustibility. Heat resistant cement is filled and sealed. The outer side of the cement resistor is mainly made of ceramic material.

6, Fuse resistor

A fuse resistor, also known as a safety resistor, is a component that combines the functions of a resistor and a fuse. When the circuit is working normally, the heat generated by the fuse resistor at the rated power is balanced with the surrounding medium. It has the function of a resistor; when the circuit is abnormally overloaded beyond its rated power, it will be fused like a face silk. Disconnecting the connected circuit acts as a fuse element, effectively protecting important components in the circuit.

7, Humidity resistance

The humidity sensitive resistor is composed of a moisture sensitive layer, an electrode and an insulator. The lithium chloride humidity sensitive resistor value become smaller with increasing humidity. The disadvantage is that the test range is small, the characteristic repeatability is not good, and is greatly affected by the temperature , and the carbon humidity sensitive resistor has the disadvantage of low temperature sensitivity, resistance value is greatly affected by temperature, due to aging characteristics it is rarely used, oxide humidity resistance performance is superior can be used for long-term, temperature effect is small, resistance and humidity change linearly

8. Photosensitive resistor

Photosensitive resistors are electronic components whose electrical conductivity changes with changes in illumination intensity, also known as photodetectors. The photoresistor is a resistor made by utilizing the photoelectric effect of the semiconductor, and the resistance value changes with the intensity of the incident light. The incident light is enhanced, the resistance is small, the incident light is weakened, and the resistance is increased.

9. Force-sensitive resistor

A force-sensitive resistor is a resistor whose resistance changes with pressure. It is called a piezoresistor in foreign countries. The effect of pressure resistance is the effect of the resistivity of a semiconductor material as a function of mechanical stress.

10, Row resistance

The row resistor is also called integrated resistor or resistor network. It is a resistor device that integrates multiple resistors. It has the characteristics of small size, high reliability and good solderability. Easy to install, suitable for multiple resistors with the same resistance value, and one of the pins is connected to the same position of the circuit.

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