Potentiometer a potentiometer is an electromechanical element that slides the brush on the resistor body to obtain an output voltage that is related to the brush displacement to a certain extent.

(1) synthetic carbon film potentiometer

The resistive body is made of ground carbon black, graphite, quartz and other materials coated on the surface of the matrix, the process is simple, is the most widely used potentiometer. It is characterized by high resolution, good wear resistance and long service life. Disadvantages are current noise, high nonlinearity, poor moisture resistance and resistance stability.

(2) organic solid potentiometer

Organic solid potentiometer is a new type of potentiometer, which USES the method of heating and molding to press the organic resistance powder into the groove of the insulator. Compared with carbon film potentiometer, organic solid potentiometer has the advantages of good heat resistance, high power and good wear resistance. But the temperature coefficient is big, the dynamic noise is big, the damp resistance performance is bad, the manufacture craft is complex, the resistance value precision is bad. Used for regulating voltage and current in miniaturized electronic equipment with high wear resistance and in ac and dc circuits.

(3) metal-glass-uranium potentiometer

The metallic vitreous uranium resistance paste is coated on the ceramic substrate by screen printing and sintered at high temperature. Features: wide resistance range, good heat resistance, strong overload capacity, moisture resistance, wear resistance, etc. Are very good, is a very promising potentiometer varieties, the disadvantages are contact resistance and current noise.

(4) wire wound potentiometer

The wire-wound potentiometer is made by winding a constant-copper wire or a nickel-chromium alloy wire around an insulating framework as a resistive body. Winding potentiometer is characterized by small contact resistance, high precision, small temperature coefficient, its disadvantages are poor resolution, low resistance value, poor high-frequency characteristics. It is mainly used for voltage divider, rheostat, instrument zero adjustment and working point.

(5) metal film potentiometer

The resistance body of the metal film potentiometer can be composed of alloy film, metal oxide film and metal foil, etc. It is characterized by high resolution, high temperature resistance, low temperature coefficient, low dynamic noise and good smoothness.

(6) conductive plastic potentiometer

A special process is used to coat DAP (dipropylene phthalate) resistance paste on the insulating body, heat and polymerize it into a resistance film, or the solid body formed by thermoplastic pressing DAP resistance powder in the groove of the insulating substrate is used as the resistance body. Features: good smoothness, excellent resolution, good wear resistance, long life, low dynamic noise, chemical corrosion resistance. Servo systems for aerospace devices, missiles, aircraft radar antennas, etc.

(7) potentiometer with switch

There are rotary switch potentiometer, push - pull switch potentiometer, push - push switch potentiometer.

(8) preset potentiometer

Preset potentiometer in the circuit, once the debugging is good, with wax sealed regulation position, in general no longer regulation.

(9) straight-slip potentiometer

The resistance value is changed by direct sliding mode.

(10) double potentiometer

There are double potentiometer and double potentiometer.

(11) contactless potentiometer

The contactless potentiometer eliminates the mechanical contact, the life is long, the plasticity is high, the spectroelectric potentiometer, the magnetic sensitive potentiometer and so on.

2. Solid core carbon resistor

A solid resistor made of carbon particles that conduct electricity, a filler, and a binder.

Features: low price, but its resistance error, noise voltage are large, poor stability, currently less used.

Wire wound resistor

It is made of high-resistance alloy wire wound on the insulating framework and coated with heat-resistant glaze insulating layer or insulating paint.

Winding resistance has low temperature coefficient, high resistance accuracy, good stability, heat and corrosion resistance, mainly used for precision high-power resistance, the disadvantage is poor high-frequency performance, time constant.

4. Film resistor

A certain resistivity material is made by evaporation by evaporation on the surface of the insulating material. Mainly as follows:

(1) carbon film resistor

Crystalline carbon is deposited on the ceramic rod skeleton. Carbon film resistor is the most widely used resistor with low cost, stable performance, wide resistance range, low temperature coefficient and voltage coefficient.

(2) metal film resistor.

The alloy materials were vaporized on the surface of ceramic rod by vacuum evaporation.

The metal film resistance has higher precision, better stability, lower noise and lower temperature coefficient than carbon film resistance. Widely used in instrumentation and communication equipment.

(3) metal oxide film resistor

Deposit a layer of metal oxide on the insulating rod. Because it is an oxide itself, so high temperature stability, heat shock, load capacity.

(4) synthetic film resistance

A suspension of conductive composite is applied to the substrate and is therefore called film resistance.

Because its conductive layer presents granular structure, so its noise is large, low precision, mainly used to manufacture high voltage, high resistance, small resistor.

5, metal glass uranium resistor

Metal powder and glass uranium powder were mixed and printed on the substrate by screen printing. Resistance to moisture, high temperature, small temperature coefficient, mainly used in thick film circuits.

6. Patch resistance

Sheet resistance is a form of metallic uranium glass resistance. Its resistance body is made of uranium glass material through high temperature sintering. The electrode is made of silver palladium alloy slurry. Small size, high precision, good stability, because it is a chip element, so the high frequency performance is good.

7. Sensitive resistance

Sensitive resistors are resistors whose device characteristics are sensitive to temperature, voltage, humidity, light, gas, magnetic field, pressure, etc. The symbol of the sensitive resistance is to add a slash to the symbol of the common resistance and mark the type of the sensitive resistance, such as t. v, etc.

(1) varistor

There are mainly silicon carbide and zinc oxide varistor, zinc oxide has more excellent characteristics.

(2) humidity sensitive resistor

It is composed of a hygroscopic layer, electrode and insulator. The hygroscopic resistor mainly includes lithium chloride hygroscopic resistor, carbon hygroscopic resistor and oxide hygroscopic resistor. The wet-sensitive resistance of lithium chloride decreases with the increase of humidity. The disadvantage is that the test range is small, the characteristic repeatability is not good, and the resistance is greatly affected by temperature. The disadvantage of carbon humidity sensitive resistor is low sensitivity at low temperature, resistance value is greatly affected by temperature, due to aging characteristics, less use.

The performance of oxide humidity sensitive resistor is superior and can be used for a long time. Tin oxide, nickel ferrate, etc.

(3) photosensitive resistor

Photoconductive resistance is an electronic element whose conductivity changes with the change of light force. When a substance is exposed to light, the concentration of carriers increases, thus increasing the conductivity. This is the photoconductive effect.

(4) gas-sensitive resistor

The main components are metal oxides. The main varieties are metal oxides gas-sensitive resistors, composite oxides ga