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　　Potentiometer wide variety of different structures! Today l Electronic here only for the parts and materials used mainly comprehensive discussion.

A resistor body
Potentiometer resistor is provided in some of the resistance values ??of the resistance member, it determines the electrical properties of the electrical properties of the main potentiometer. Resistor should have good resistance stability, small temperature coefficient of resistance and static noise. To improve reliability, it should be resistant to moisture, heat resistance, wear resistance, oxidation resistance, high resistance to thermal loads and sudden changes in other properties. Contactless potentiometer resistor element, on which the movable contact contacts and slides for resistor surface having a low resistivity so as to contact with the moving contact resistance is small; while the surface resistivity should be evenly distributed in order to preserve effective electrical contact resistance within the itinerary changes and track small changes in resistance, the resistance can get better regularity properties. Resistor surface should have an appropriate finish, hardness and wear resistance of some, to ensure its mechanical durability. Wirewound potentiometers on the resistance wire is wound on the skeleton, made of circular or spiral and other resistors, thin film or thick film potentiometer, is the resistance of the film formed on the substrate, the public, mostly horseshoe shape, arc-shaped or elongated. For the synthesis of solid core potentiometer, it is compression molded in the base of the horseshoe-shaped or elongated resistive track. Second, the skeleton and matrix
Skeleton is an insulating support wire potentiometer resistor. Support substrate (or substrate) non-wire potentiometer resistor.
Good skeleton and matrix commonly used insulation material, requiring heat, resistant to moisture, electrical insulation, chemical stability and good thermal conductivity, and only a certain mechanical strength. Generally laminated sheet of paper, cloth is laminated panels, plastics, ceramics, glass and surface through insulated copper, aluminum and aluminum alloy surface by this i insulated metal substrate should have sufficient surface of the insulating this framework matrix has good heat resistance, but also easy to shape.
Third, the brushes slide Q and center contact ring piece.
Potentiometer slide along the resistor and the input voltage leads movable contact member, said brush 1 brush made of metallic material, should have a high tensile strength and good elongation, and easy to weld, ease of processing and assembly. Metal brush should be used in good elastic metal material, so that the movable contact of the brush body and elastic pressure resistance. Elastic material should have a high elastic limit, yield strength and the like. In the long-term use, the resilient pressure changes the brush smaller, the higher the contact reliability. Metal brush commonly used materials: beryllium copper, phosphor bronze, nickel silver, the silver chrome, platinum-nickel alloy, platinum-iridium alloy, pound iridium alloy, gold, silver alloy. Precious metal-based alloys with a high resistance to oxidation and corrosion, even under high temperature and humidity conditions phases. When stable; the contact resistance variation is small, commonly used in precision potentiometers'
2. Slide arm (or slider)
The sliding arm is connected to the shaft (or slip handle) and the brush member, it will be the shaft (or slip handle) the movement of the shaft brush, brush drive arm sliding body sliding material on the potentiometer resistor structure according to the choice of metal material or non-metallic materials. Such as the use resilient metal material, the slide arm acts as an elastic pressure exerted on the brush; such as the use of a rigid material, the brush should have a certain flexibility, elastic or other elastic parts exert pressure on the brush. A material commonly used for the slide arm pivot leg cloth, paper, rubber, plastic branch, brass, silver, copper and phosphor bronze. Metallic materials normally takes plating layer.
3. Contact spring
Contact spring is connected to the brush and the collecting member groove member, the electrical output of the brush will be passed to the current collector and the lead member Switzerland. Contact between the spring and the current collecting member is a movable contact type connection, the contact spring for potentiometer mechanical durability, stability and dynamic contact with a great noise. Therefore, the contact spring should have good flexibility to ensure manifold pressure member has a certain flexibility; it also has good electrical and thermal conductivity, hardness and wear resistance should match the manifold member. Commonly used materials are phosphor bronze and the bronze. Reed contacts regularly with the brush or sliding arm integrally formed.
Fourth, rectifier and terminations
1. Collecting member (also known as conductive ring)
Collecting member is a lead member electrically connected between the end of the contact spring. Collecting member Tuo good conductivity, the contact reed contact resistance, high mechanical strength and good wear resistance. Usually brass, aluminum or aluminum alloy; some materials to be electroplated protective layer. The metallic glass glaze potential manifold member is burned on the ceramic substrate infiltration silver layer, synthetic organic solid core potentiometer collector items available low resistance conductive powder repression.
2. Terminals
The pigtail is a fixed end and the two ends of the variable resistor element of the brush member and the outer leads connected to the circuit. With switch potentiometer switch also leads the Swiss. There tap-tap potentiometer terminals, it is wiring leads Swiss a point on the effective power stroke. All leads and internal Swiss should have good electrical connection. Terminals should have good electrical conductivity, corrosion resistance and oxidation resistance, and has a certain flexural, tensile mechanical strength and good weldability.
Terminations commonly used materials are brass and iron-nickel alloys, often by plating nickel, tin, silver, gold, etc. as a protective layer. Fifth, derailleur, sliding steel, the screw shaft and plug
1. Shaft, slide the handle, the screw shaft is a rotary potentiometer introducing rotary motion member; slide the handle straight slide potentiometer introduction of linear motion member; screw is screw-driven introduction of multi-turn potentiometer rotary motion member. Combining them with other sliding contact member or a rotational member driving mechanism. Drive mechanism is introduced into the mechanical movement from the outside, driven movable contact (wiper) sliding along resistive element constituting part of the general. It is called the rotation system in the rotary potentiometer; called sliding system Slide potentiometer vessel.
Shaft promised to have high dimensional accuracy and finish, to ensure smooth rotating or sliding, feel good, power noise; it should also have a certain mechanical strength to ensure that no deformation and fracture hair now passed through the force in i liter. The potentiometer assembly member towels and all electrical components must forever.
These components usually brass, steel, aluminum, nickel-chromium steel or plastic material. Shaft made of steel and brass-plated handcuffs required protective layer; corrosion-resistant nickel-chromium steel, without metallised protective layer, commonly used in precision potentiometers; and corrosion-resistant aluminum alloy also worry point, and light weight, cheap, but worse than the strength of nickel-chromium steel. Plastic f can save a metallic material, compression molding and processing efficiency is high, the product of a specified high voltage insulated shaft as well as security.
2. Bushings
Bushings keep moving with precision and safety cylinder shaft (or screw), which may form a whole with the base member Hugh. Usually the threaded bush mounting member also serves the role. Fast potentiometer, using ball bearings b its high precision, low friction; rotation long life. Journal of the sleeve material should be easy to port workers, high precision bore size, have sufficient mechanical strength, usually brass, steel and aluminum and other materials, some need plating layer, it also uses plastic insulating sleeve.
Sixth, and protrudes from the base
1. Base (also known as base)
And the support base is installed resistor, leads to the base member and the elimination of the current collecting member and other components. Common base ceramics, plastic or metal material. Metal glaze glass, metal films and high-power wirewound potentiometers common ceramic substrate; a base commonly used aluminum alloy precision wirewound potentiometers. Easily processed into various shapes of plastic, mechanical and electrical properties of rape, "and low price, light weight, corrosion resistance, it is widely used in organic synthesis, solid core, synthetic carbon film and wirewound potentiometers in general.
The base and the sleeve usually be mated or riveted together. Sometimes pressed into the base metal blue plate method to enhance the potential of the cooling capacity. Some potentiometer base and the base is an integral member, such as a synthetic organic solid core potentiometer is.
2. shell
Shell is mainly packaging and protective potential member of the housing, which protects the internal components from dust and moisture role. Metal is also used in the ground, and act as a shield to suppress the interference of external electric field.
The enclosure shall have a high mechanical strength, corrosion resistance and moisture characteristics. Requirements ground shield housing application weldability good metal or ammonium material layer.
Commonly used housing material brass, steel, aluminum and plastic.
Seven, the stopper
The stopper drive mechanism is used to limit the stroke of the device, stopper usually can not exist independently, it can be with the housing or base, but also with the first flow member or terminations as a whole.
Eight switch
Switching device with switch potentiometer potentiometer is driven by a shaft to achieve switching on and off the power supply apparatus. Many forms of switches, can be divided into common rotary dial head, rotary and spring push-pull three.
Strong head rotary switch structure is insulated shaft driven cam, cam dial head pinch so high, so that the switch-off position into a position from the pass. Structure spring rotary switch is driven by the rotation axis of the pendulum block, the associated end of the spring pendulum block, the other end of the contact piece linkage, since the pendulum swing block, forcing the spring bounce, thus promoting the movable contact piece and fixed contacts quickly turn on or disconnect. Both small current through the switch, you can use material nickel silver, phosphor bronze, copper-chromium alloy. Each time the switch must rotate the potentiometer to the zero position, it reduces the actual life of the potentiometer. Both potentiometer with switch, SPST often used for low current, low voltage electronic equipment, the general as transistor radios and the like. Push-pull switch structure is shaft axially outer or inner pull-push motion, with the action of the spring slider decline or reset, the contact rod and two contacts quickly turn on or off. Good contact reliability of such a switch. Silver - or silver brocade - tungsten alloy, can anti-arc, allowing a larger current through the switch. Any adjustment potentiometer in good position you can open and close by the axial sliding motion switch, so the re-use, do not need to adjust the potentiometer, to extend the life of the potentiometer is very beneficial. This switch is DPDT general formula for television and premium income guitar maker.
Nine, rubber band
Rubber band is from the seal member in the potentiometer, used to prevent moisture intrusion. Often placed between the shaft and the sleeve, the housing and the base, the drive mechanism and housing. When used between shaft and hub, but also from increased start force; moment and make a uniform rotational torque effect. Sealing potentiometer often placed 2-3 in the group between the shaft and the rubber bushings to improve sealing performance.