What is a potentiometer? What is a potentiometer?

What is a potentiometer? What is a potentiometer?

Potentiometer is an electromechanical component. It uses the brush to slide on the resistor to obtain an output voltage that is related to the brush displacement.
1.1 Synthetic carbon film potentiometer
The resistor is made of ground carbon black, graphite, quartz and other materials coated on the surface of the substrate. The process is simple and it is the most widely used potentiometer. The characteristics are high resolution, good wear resistance and long life. The disadvantages are current noise, large nonlinearity, poor moisture resistance and resistance stability.
1.2 Organic solid potentiometer
Organic solid potentiometer is a new type of potentiometer. It uses the method of heating and plastic pressing to press organic resistor powder into the groove of the insulator. Compared with carbon film potentiometer, organic solid potentiometer has the advantages of good heat resistance, high power, high reliability and good wear resistance. However, it has a large temperature coefficient, large dynamic noise, poor moisture resistance, complex manufacturing process and poor resistance accuracy. It is used to adjust voltage and current in miniaturized, highly reliable and highly wear-resistant electronic equipment and AC and DC circuits.
1.3 Metal Glass Uranium Potentiometer
The metal glass uranium resistor slurry is coated on the ceramic substrate according to a certain pattern by screen printing, and then sintered at high temperature. The characteristics are: wide resistance range, good heat resistance, strong overload capacity, moisture resistance, wear resistance, etc. It is a very promising potentiometer variety. The disadvantages are large contact resistance and current noise.
1.4 Wire Wound Potentiometer
The wire wound potentiometer is made by using constantan wire or nickel-chromium alloy wire as the resistor body and winding it on an insulating skeleton. The characteristics of the wire wound potentiometer are small contact resistance, high precision, and small temperature coefficient. Its disadvantages are poor resolution, low resistance, and poor high-frequency characteristics. It is mainly used as a voltage divider, a rheostat, zero adjustment and working point in instruments, etc.
1.5 Metal Film Potentiometer
The resistor body of the metal film potentiometer can be composed of alloy film, metal oxide film, metal foil, etc. It is characterized by high resolution, high temperature resistance, small temperature coefficient, small dynamic noise, and good smoothness.
1.6 Conductive plastic potentiometer
Use a special process to coat DAP (dipropylene phthalate) resistor paste on the insulating body, heat and polymerize it into a resistor film, or heat and press DAP resistor powder into the groove of the insulating substrate to form a solid body as a resistor body. Features: good smoothness, excellent resolution, good wear resistance, long life, low dynamic noise, high reliability, and chemical corrosion resistance. Used in servo systems of space devices, missiles, and aircraft radar antennas.
1.7 Potentiometer with switch
There are rotary switch potentiometers, push-pull switch potentiometers, and push-push switch potentiometers .
1.8 Pre-adjustment potentiometers
Once the pre-adjustment potentiometer is debugged in the circuit, the adjustment position is sealed with wax and it is no longer adjusted under normal circumstances.
1.9 Direct slide potentiometer
The resistance value is changed by direct sliding.
1.10 Double-connected potentiometer
There are heteroaxial double-connected potentiometers and coaxial double-connected potentiometers.
1.11 Contactless potentiometer The contactless potentiometer
eliminates mechanical contact, has a long life and high reliability, and is divided into photoelectric potentiometers, magnetic sensitive potentiometers, etc.

Potentiometer inspection. When inspecting a potentiometer, first turn the knob to see if it rotates smoothly, if the switch is flexible, and if the "click" sound is crisp when the switch is on and off. Listen to the friction sound between the internal contact point and the resistor of the potentiometer. If there is a "rustling" sound, it means that the quality is not good. When testing with a multimeter, first select the appropriate resistance position of the multimeter according to the resistance value of the potentiometer to be tested, and then perform the inspection according to the following method.

A Use the ohmmeter of a multimeter to measure the two ends of "1" and "2". The reading should be the nominal resistance of the potentiometer. If the pointer of the multimeter does not move or the resistance value is very different, it indicates that the potentiometer is damaged.

B Check whether the active arm of the potentiometer is in good contact with the resistor. Use the ohmmeter of the multimeter to measure the two ends of "1" and "2" (or "2" and "3"), and rotate the shaft of the potentiometer counterclockwise to a position close to "off". At this time, the smaller the resistance value, the better. Then slowly rotate the shaft handle clockwise, the resistance value should gradually increase, and the pointer in the meter should move smoothly. When the shaft handle is rotated to the extreme position "3", the resistance value should be close to the nominal value of the potentiometer. If the pointer of the multimeter jumps during the rotation of the shaft handle of the potentiometer, it means that the active contact has a poor contact fault.