Potentiometer usage specifications and precautions2021

The potentiometer is a resistance element with three lead-out ends and the resistance value can be adjusted according to a certain change rule. Today, let’s take a look at the function of the potentiometer, its use specifications and precautions.

The role of potentiometer

The main functions of the potentiometer in the circuit are as follows:

1. Used as a voltage divider

The potentiometer is a continuously adjustable resistor. When the rotary or sliding handle of the potentiometer is adjusted, the movable contact slides on the resistor body. At this time, at the output end of the potentiometer, an output voltage that has a certain relationship with the external voltage of the potentiometer and the angle or stroke of the movable arm can be obtained.

2. Used as a rheostat

When the potentiometer is used as a rheostat, it should be connected as a two-end device, so that within the stroke range of the potentiometer, a smooth and continuous resistance value can be obtained.

3. Used as a current controller

When the potentiometer is used as a current controller, one of the selected current output terminals must be the sliding contact terminal.

Potentiometer usage specifications and precautions

1. Avoid condensation or water droplets on the surface of the potentiometer, and avoid using it in a humid place to prevent insulation deterioration or short circuit.

2. When installing the "rotating type" potentiometer, the nut should not be too tight to avoid damage to the thread or poor rotation; when installing the "steel case straight sliding type" potentiometer, avoid using too long screws, otherwise it may be possible Obstruct the movement of the sliding handle, and even directly damage the potentiometer itself.

3. During the process of putting the potentiometer on the knob, the pushing force used cannot exceed the parameter index of the shaft pushing and pulling force in the "Specification Book", otherwise it may cause damage to the potentiometer.

4. The rotary operating force (rotation or sliding) of the potentiometer will become lighter as the temperature rises, and tighten as the temperature drops. If the potentiometer is used in a low temperature environment, it needs to be explained, so that special low temperature resistant grease can be used.

5. The shaft or sliding handle of the potentiometer should be as short as possible when designing it. The shorter the shaft or sliding handle, the better and stable the hand feel. On the contrary, the longer the shaking, the greater the shaking, and the feel is easy to change.

6. The resistor body of the potentiometer is mostly made of polycarbonate synthetic resin. Avoid contact with the following items: ammonia, other amines, aqueous alkaline solutions, aromatic hydrocarbons, ketones, and lipid hydrocarbons. Strong chemicals (excessive acid-base value), etc., otherwise it will affect its performance.

7. If the terminal of the potentiometer is soldered, if the soldering temperature is too high or the time is too long, it may cause damage to the potentiometer. The pin terminal should be soldered at 235℃±5℃ within 3 seconds, and the soldering should be more than 1.5mm away from the potentiometer body. Do not use solder to flow through the circuit board when soldering; solder wire terminal should be soldered at 350℃± 10℃, complete within 3 seconds. And the terminal should avoid heavy pressure, otherwise it is easy to cause poor contact.

8. When the potentiometer is soldering, the height of the rosin (flux) entering the printed circuit board should be adjusted properly, and the flux should be prevented from entering the potentiometer, otherwise it will cause poor contact between the brush and the resistor body, resulting in INT and poor noise.

9. The potentiometer is best used in the voltage adjustment structure, and the connection method should be "1" pin grounding; the current adjustment structure should be avoided, because the contact resistance between the resistor and the contact piece is not conducive to the passage of large currents.