The resistor is usually called the resistance, is one of the most common electronic components, a wide range of applications. To understand the main para. To understand the main parameters and characteristics of the manufacturing process of resistance resistance for us to learn, understand, there is a great help, use the correct selection of resistance.
The resistor is made of higher resistivity of the material, it has a stabilizing or adjusting the current, voltage effect in the circuit.
(1) can adjust according to the resistance value
With a fixed resistor, variable resistor two categories.
The resistance of the resistor is called fixed fixed resistor; resistor continuously variable called variable resistance (including trimming resistor and potentiometer).
(2) according to the manufacture materials
Carbon film resistors, metal film resistors, Wirewound resistors etc..
(3) according to the different outlets
Axial lead resistor and no lead resistor.
(4) by use of different sub
There is a general resistor, precision resistors, high frequency resistor, thermal resistor, photosensitive resistors, varistors etc..
The following classification introduced these resistance.
1, carbon film resistor
Carbon film resistor is separating the organic compounds of carbon in vacuum furnace high temperature, and then make the carbon deposition on the surface of the ceramic substrate is formed with a certain resistance (resistance value can be obtained by changing carbon film thickness or length) of carbon membrane (resistor), finally properly after a joint cut thin, a resistor and epoxy in its surface coated with resin sealing protection and produced, so it is also called the thermal decomposition of carbon film resistor.
The main characteristics of carbon membrane resistance is relatively good high frequency characteristics, wide resistance range, the price is cheap, but poor accuracy. Is China's largest production, the most widely used general resistor. It is widely used in electronic products, such as TV recorder.
2, metal film resistor
Metal film resistor is under vacuum conditions, deposited on the ceramic substrate made of a layer of alloy powder. Different resistance can be obtained by changing the thickness of metal film or length. Metal film resistors are mainly metal film resistors (CN) metal oxide film resistor (RS) and metal glaze film resistors (RK).
Due to the advantages of metal film resistor with large power, low noise, small temperature coefficient, high precision, good performance of high frequency, wide resistance range, is widely applied in the advanced audio, computer, testing instrument, automatic control and other high-end equipment.
3, precision metal film resistors
Precision metal film resistors with alloy vacuum plating technology for nickel cadmium or similar, the resistance material of the membrane on the white surface of the rod, after cutting debug resistance, in order to achieve the final requirements precision resistance. Precision metal film resistor resistance value precision, tolerance range of small, mainly used in resistance requires more sophisticated occasions.
4, impact resistance type glass glaze film power resistor
Impact resistant type glass glaze film power resistance is to use metallic glass enamel coating on the magnetic resistance and a production, has excellent impact resistance characteristics and high temperature stability, mainly used in high power devices.
5, wire wound resistor
Wire wound resistor is the resistance wire (copper wire Kang or manganese copper) around the heat-resistant porcelain body, the surface is coated with heat resistance, moisture, corrosion protective coatings and incombustible. Winding resistance and has good heat resistance, low temperature coefficient, light weight, resistance to short time advantages, small noise, stable resistance load, inductance is low, but its high frequency characteristics is poor, so it is widely used in the low frequency precision instruments.
6, cement resistor
Cement resistance is also a wirewound resistor, is resistance wire around in the heat-resistant porcelain pieces, outside with heat resistance, moisture and corrosion resistant material protection and fixed. Cement resistance is usually the resistor body into the square porcelain box, with special non flame cement filling and sealing and become, because of its shape like a white rectangular cement block, so that cement resistor.
Cement resistor has the characteristics of high power, good heat dissipation, high stability, moisture resistance, seismic etc.. Mainly used in power circuits, such as power supply circuit overcurrent detection, protection circuit, a power output circuit audio power amplifier.
7, insurance resistor
Insurance resistance also known as fuse resistor, resistor and the fuse, insurance has two functions, is usually used as resistors, once the current exception will play its role to protect equipment fuse.
Insurance resistance plays a dual role of fuse and resistance in the circuit, the main application in the power output circuit. Insurance of the resistance value of the resistor is generally small (a few ohms to several tens of ohms), power is also smaller (1/8---1W).
Circuit load short-circuit fault, over current occurs, the temperature will rise to insurance resistor of 500℃ ---600 ℃ in a short period of time, then the resistance layer heated spalling plays the role of fuses, fuse, to improve the security purpose.
8, network resistance
Resistor network is also called exclusion. Resistor network consists of multiple resistors centralized package together, a combination made of composite resistance. Network resistor assembly is convenient, the installation density advantages, have been widely used in electronic circuits.
9, surface mount resistor
Surface mount resistor is also called non lead resistance, chip resistors, chip resistors, resistor SMD.
Surface mount resistor mainly has two kinds of rectangular and cylindrical shape. Rectangular surface mount resistor is mainly composed of a ceramic substrate and a resistive film, protective layer and a metal terminal electrode of four parts. Ceramic substrate using three general oxidation of 96% of the two aluminum (AL2O3) ceramics; resistance film usually use resistance slurry composed of RuO2 printed on the substrate, and then sintering; cover on the resistive film protection layer typically uses printed glass paste material after firing glaze; terminal electrode is made of three layers of materials composition: it is composed of the inner layer (i.e., the contact resistance of the film part) using the contact resistance is small, Ag-Pd alloy with strong adhesion; the middle layer is Ni, is mainly used to prevent the end electrode detachment; the outer layer is weldable layer composed of Sn or Sn-Pb or Sn-Ce alloy.
Cylindrical surface mount resistor is in high alumina ceramic substrate is coated with metal or carbon film resistor, then in the pressure of the two ends of the upper metal electrode cap, through the threaded groove method determine the resistance and then brush a layer of heat insulating paint and the surface sprayed with color coded signs and.
10, NTC, PTC thermistor
The NTC thermistor is one kind has the negative temperature coefficient thermosensitive element changes, the resistance decreased with the increase in temperature, can be used to stabilize the work point of the circuit. The PTC thermistor is a kind of positive temperature coefficient thermosensitive element change. To reach a certain temperature, the resistance value decreased slowly with temperature increasing, when the above this temperature, the resistance value increases rapidly. The specific temperature called the Curie point. The PTC thermistor Curie point by changing the material of each component varies in proportion to. It is widely used in household appliances, such as TV degaussing resistor, electric cooker temperature controller.