EN   中文 
TEL :+86(0752)-690 2927

News

You are here : Home  >>  News  >>  Industry Trends  >>  View Details

Precautions for the use of carbon film potentiometers

Date:2018-03-20 17:57:09        Hits:435 
A carbon film potentiometer is made of a layer of carbon film coated on a horseshoe-shaped sheet of paper. There are three kinds of relationship between the change of the resistance and the position of the middle contact, which are linear, logarithmic and exponential.
Precautions for the use of carbon film potentiometers
A carbon film potentiometer is made of a layer of carbon film coated on a horseshoe-shaped sheet of paper. There are three kinds of relationship between the change of the resistance and the position of the middle contact, which are linear, logarithmic and exponential. The carbon film potentiometer has large, small, miniature, and some with the switch to make a switching potentiometer.
From the outside, pulse potentiometer and ordinary potentiometer are the same as the three pins, but inside and pin 1 and 2 is connected to two different lengths of the metal sheet and the static, pin 3 is connected to a circle with 12 or 24 teeth of the metal plate. When the pulse potentiometer rotates, there are four states: that is, pin 3 is connected to pin 1, and pin 3 is connected to pin 2 and pin 1.Pin 3 is connected to pin 2, pin 3 and pin 2 and pin 1 are all disconnected


Huizhou Lesen Precision Electronic Co. Ltd introduce eight notices for the use of carbon film potentiometers
When we replace the carbon film potentiometer, should pay attention to the potentiometer axial length and shape of shaft end should be matched with the original knob, it can not find the original prototype resistance potentiometer, resistance type potentiometer and available similar substitution in addition, the use of carbon film potentiometer the matters needing attention include the following specific. The contents are as follows.
Note 1. The voltage drop generated when the current flows through a high resistance carbon film potentiometer should not exceed the maximum working voltage allowed by the potentiometer.
Note2. In order to prevent the carbon film potentiometers from changing or burning, the working current of the small resistance potentiometer should not exceed the maximum allowable current of the contacts.
Note3. Various trimming potentiometers can be directly installed on printed circuit boards, but we should pay attention to the arrangement of adjacent elements, so as to ensure that the potentiometer is adjusted conveniently without affecting the adjacent components.
Note4. Carbon film potentiometer must ensure firm and reliable installation, should be in place to tighten the nut fastening application of sufficient force to defense towards the use of the process for loosening deformation phenomena, caused induced circuit fault and other elements together.
Note5. Because some parts of the potentiometer are made of synthetic resin such as polycarbonic anhydrase, so don't use in the environment containing ammonia, amine and alkali solution and aromatic hydrocarbons, ketones, halogenated hydrocarbons and other chemical concentration is high, in order to prolong the service life of the potentiometer.


Note6. The quality of the carbon film potentiometer should be checked before use. The shaft handle of the high-quality potentiometer should be rotated flexibly and properly, without mechanical noise; Check nominal resistance values with multimeter and meet the requirements;If the resistance value between the fixed end of the potentiometer and the slide terminal is measured with a multimeter, the needle should be rotated smoothly without jumping when rotating the shaft of the potentiometer slowly.
Note7. Unsealed potentiometers are most likely to have large noise faults, mainly due to oil pollution and wear. At this point, you can't solve this problem with the method of coating the lubricating oil. Instead, the lubricating oil will aggravate the accumulation of internal dust and conductive particles. The correct treatment is to use a cotton ball dipped in anhydrous alcohol to gently swab the dirt on the resistance sheet and to remove the oil from the contact brush and the elicitation reed.
Note8. The carbon film potentiometer should not be used in excess of the load and should be used within the rated value. When the potentiometer is used as a rheostat to regulate the operation of the current, the allowable power consumption should be proportional to the stroke of the contact contact brush, so as to ensure that the current passed does not exceed the maximum value of the potentiometer, and prevents the potentiometer's failure due to partial overload. In order to prevent the resistance of potentiometer from adjusting to a maximum value near zero, it is better to connect a current limiting resistor to avoid damaging the potentiometer.
Characteristics of carbon film potentiometers
1.The range of resistance is wide, and its resistance can range from a few hundred to a few trillion
2.Because its resistance can change continuously, the resolution is high.
3.It can be made into various types of potentiometers, such as the precision potentiometer, function potentiometer, etc.
4.Easy to make, cheap to make.
5.The variety of varieties can meet the requirements of household electrical equipment, so it is widely used.
6.life was longer
7.The power is small, generally below 2W.
8.Humidity resistance, temperature tolerance, only applicable to the better environment.
9.The sliding noise is large and the temperature coefficient is large.
 
The carbon film potentiometer is mainly used in the mixer, audio, car audio, TV, power amplifier, electronic message equipment, headset, radio, toy, DVD/VCD, medical equipment, lamps, and lanterns.