Type:Rotary Potentiometer Technology:Carbon Composition Resistance Tolerance:20% Operating Temperature:C
It is made of resistance wire wound on the ring-shaped skeleton. It is characterized by a small resistance range and a large power.
Wirewound potentiometers have the advantages of high precision, good stability, small temperature coefficient, reliable contact, etc., and high temperature resistance, strong power load capacity.
The disadvantage of wire-wound potentiometers is that the resistance range is not wide enough, the high-frequency performance is poor, and the resolution is not high, and the wire-wound potentiometers with high resistance are easy to break, have a larger size, and have a higher price.
1. Most of the resistors of wire-wound potentiometers are made of polycarbonate synthetic resin. Avoid contact with the following items: ammonia, other amines, alkaline aqueous solutions, aromatic hydrocarbons, ketones, and lipid hydrocarbons. Compounds, strong chemicals (acid value is too high), etc., otherwise it will affect its performance.
2. When welding the terminals of the wirewound potentiometer, avoid using water-based flux, otherwise it will promote metal oxidation and moldy materials; avoid using inferior flux, poor soldering may cause difficulty in soldering, resulting in poor contact or open circuit.
3. If the welding temperature of the terminal of the wire wound potentiometer is too high or the time is too long, it may cause damage to the potentiometer. Pin-type terminals should be soldered at 235 ° C ± 5 ° C within 3 seconds. Soldering should be more than 1.5MM away from the potentiometer body. Do not use solder to flow through the circuit board during soldering; solder wire-type terminals should be 350 ° C ± 10 ℃, completed within 3 seconds. And the terminal should avoid heavy pressure, otherwise it is easy to cause poor contact.
4. During soldering, the height of the rosin (flux) entering the printing machine board is adjusted properly, and the flux should be prevented from intruding into the inside of the wire wound potentiometer, otherwise it will cause poor contact between the brush and the resistor, resulting in INT and bad noise.
5. Wire-wound potentiometers are best used in voltage-adjusting structures, and the wiring method should be selected to “1” pin to ground; should avoid using current-adjusting structure, because the contact resistance between the resistor and the contact piece is not conducive to the passage of large currents.
6. The surface of the wire-wound potentiometer should avoid condensation or water droplets, and avoid use in wet places to prevent deterioration of the insulation or short circuit.
7. When installing the “rotary” potentiometer, the strength should not be too tight when fixing the nut, so as to avoid damage to the teeth or poor rotation, etc .; when installing the “iron shell straight-slide” wire wound potentiometer, avoid using too long screws, otherwise it may be It hinders the movement of the slider and even directly damages the potentiometer itself.
8. In the process of putting the knob around the potentiometer, the pushing force used should not be too large (it cannot exceed the parameter index of the pushing and pulling force of the shaft in the “Specifications”), otherwise it may cause damage to the potentiometer.
9. The operating force (rotation or sliding) of the wire-wound potentiometer will become lighter as the temperature increases, and tighten as the temperature decreases. If the potentiometer is used in a low-temperature environment, it needs to be explained in order to use special low-temperature grease.
10. The shaft or slider of the wire wound potentiometer should be designed to be as short as possible. The shorter the length of the shaft or slider, the better and more stable it feels. Conversely, the longer the shaking, the greater the change in feel.
11. The power of the carbon film of the wire wound potentiometer can withstand the surrounding temperature of 70 ℃, when the use temperature is higher than 70 ℃, it may lose its power.
The wire-wound potentiometer is composed of a resistance wire coil wound on the skeleton and a sliding arm moving along the potentiometer and the brushes on it. The skeleton cross-section should be equal everywhere. to make.