Commonly used potentiometer
1. Wire wound potentiometer
( 1 ) Structure
Alloy resistance wire wound around the insulation skeleton into a resistor, the center tap reed on the resistance wire is relatively slippery move. By this method, a precision wirewound potentiometer with a precision of 0.1 % and a high power potentiometer with a rated power of over 100 W can be made. The utility model can be divided into ordinary type, precision type and fine adjustment type wire wound potentiometer; according to the law of resistance change, it can be divided into linear and nonlinear.
(2)Characteristic.
The accuracy of linear potentiometer is easy to control, the stability is good, the temperature coefficient of resistance is small, the noise is small, and the resistance is low.
High temperature, but a narrow range of resistance, usually from several ohms to tens of thousands of ohms.
2. Asynthetic film potentiometer.
(1)Structure
The composite membrane potentiometer is coated with a layer of synthetic carbon film on the insulating substrate, then polymerized to form carbon membrane and then combined with other parts. The resistance of this potentiometer is linear and nonlinear, and the shaft end structure is divided into two types: locking and unlocking.
(2)Characteristic
Its resistance value changes continuously, the resolution is high, and the resistance range is wide.
(100 ohm ~5 M ohm). It has poor adaptability to temperature and humidity and short service life. The rated power is 0.125W, 0.5W, 1W and 2W, and the accuracy is generally 20%.
3. Organic solid potentiometer
(1)Structure
The resistance powder is made of conductive material and organic filler and thermosetting resin, and is formed on the base by hot pressing solid electrocardiographic resistance body.
(2)Characteristic
This kind of potentiometer has the advantages of simple structure, high temperature resistance, small volume, long service life, high reliability, low pressure resistance, large noise and large rotation moment. It is mostly used in circuits with high reliability. The resistance range is 47 ohms ~4.7 trillion ohms, the power is 0.25 ~2W, the precision is 5%, 10% and 20%.
4. Multi loop potentiometer
Multiring potentiometer is a precision potentiometer. When adjusting the resistance value, it needs to rotate the rotating shaft several times, so the accuracy is high. When the resistance needs to be adjusted in a large range, multi cycle potentiometers can be used. There are many kinds of multi ring potentiometers, such as winding, metal film type, organic solid type, etc.
5. Conductive plastic potentiometer
The resistor body of conductive plastic potentiometer is made of carbon black, graphite, ultrafine metal powder and phospho benzene two carboxylic acid, diallyl ester plastic and adhesive. It has good wear resistance, reliable contact, strong resolution, long life, but poor moisture resistance. In addition to the above contact potentiometer, there is also a contactless potentiometer. The non-contact potentiometer does not have mechanical contact, so it overcomes the shortcomings of unstable contact resistance, sliding noise and breaking.
6. Potentiometer with Switch
The potentiometer has a rotary switch potentiometer, a push pull switch potentiometer and a push switch potentiometer.
7. Contactless potentiometer.
The contactless potentiometer eliminates mechanical contact, has long service life and high reliability, and is divided into photoelectric potentiometers and magnetic potentiometers.
8. A tablet potentiometer.
The surface mounted potentiometer is also called a chip potentiometer. It includes flaky, cylindrical, flat rectangles and other structures. Their resistance base is 1, 2 and 5, such as 10kΩ, 20kΩ, 50kΩ and 100kΩ.
There are 4 different configurations of the tablet potentiometers.
(1)The potentiometer is further divided into a direct drive reed structure and an insulated shaft driven reed structure. The open type potentiometer has no housing protection, dust and moisture are easy to enter the product. It has a certain impact on the performance, but the price is low, so it is often used in the consumer electronics.
( 2 ) The structure of the dustproof structure with a shell or a shield, dust and moisture are not easy to enter the product, the performance is good, which is mostly used in investment electronic machine and high-end consumer electronics machine.
( 3 ) The structure of this potentiometer, which belongs to the fine adjustment type with good performance, but the price is very high, it is mainly used in the precision investment electronic machine
( 4 ) The potentiometer has two forms, cylindrical and flat rectangular, which has the characteristics of convenient adjustment, reliability and long service life, it is often used in high-end electronic products. The structure of the cylindrical potentiometer is divided into two kinds of side harmonic terms.