陕西快乐十分走势图

News Category
Contact Us

HONGKONG CHANGWANG GROUP.,LIMITED
ADD: Shabian Industrial Zone, Chang An Town, DongGuan City, Guang Dong Province
TEL: 0769-85342575
FAX: 0769-85342576
Mobile: 13712812287
Contact: Mr. Zheng  Miss Luo

Online Service
  Service   Service  
News
Chip Resistor: thick film resistor / precision wirewound resistor / film resistance characteristics of comparative advantages and disadvantages
Editor:    Hit: 44  Date: 2012-9-27
Chip Resistor: thick film resistor / precision wirewound resistor / film resistance characteristics of comparative advantages and disadvantages

  The current through the resistor element generates heat, and each of the materials of the thermal reaction causes the device to occur the expansion or contraction of the mechanical changes. Ambient temperature conditions will produce the same result. Therefore, the ideal resistive element should be able to self-balancing based on these natural phenomena, in the resistor process maintain physical consistency, the use of the process do not have thermal effects or stress effect compensation, thereby improving the stability of the system.

Thick Film Resistors

  As mentioned earlier, the size, volume and weight, wirewound resistors impossible Chip. Although the accuracy is lower than a wirewound resistor, but have a higher resistance density (high resistance / small size) and lower cost, the thick film resistor is widely used. And thin film resistors and metal foil resistors, thick film resistors frequency response speed, but the the resistance technology currently used, the maximum noise. Although the accuracy is lower than other technologies, but the reason we discussed this thick film resistor technology is widely used in almost every kind of circuit, including high-precision circuit less precision part.

  Relying on the contact between the particles in the glass matrix forming a resistor thick film resistor。 These contacts constitute a complete resistance, but heat strain will interrupt the contact。 Parallel, thick film resistors will not open in most cases, but the resistance over time and temperature continues to increase. Therefore, compared with the other resistor technology, thick film resistors, poor stability (time, temperature, and power).

  Clusters of charge movement due to the structure, a granular structure also makes the thick-film resistors to generate a high noise。 Given size, the higher the resistance value of the metal component is less, the higher the noise, the worse the stability. The glass component in the thick-film resistor structure to form a glass phase in the resistor process protection layer, and thus the moisture resistance of the thick film resistor is higher than the thin film resistor.

 Thin Film Chip Resistors

  The thin film resistor by the thickness of the ceramic substrate for the deposited metal layer of 50 Å to 250 Å (by vacuum or sputtering process). Film resistance per unit area of ​​resistance is higher than wirewound resistors or Bulk Metal ® metal foil resistors, and cheaper. Require high resistance and precision requirements for middle level thin film resistors are more economical and space-saving.

  They are sensitive to the thickness of the deposited layer having an optimum temperature, but severely limits the range of possible resistance values ​​of the resistance value generated by the optimum film thickness. Therefore, using a variety of the thickness of the deposited layer can achieve a range of different resistance values​​。 The stability of the resistance of the film by the influence of the temperature rise. The stability of the aging process of the thin film resistors to achieve the desired film thickness of different resistance values ​​are different, so the entire resistance range is variable。 This chemical / mechanical aging include alloy high-temperature oxidation resistance。 In addition, changing the optimal film thickness will seriously affect the TCR. As the thin deposited layer is more easily oxidized, therefore the rate of degradation of the high resistance thin film resistor is very high.

  Since the metal less, thin film resistors in the humid conditions easily Etch. Immersed in the encapsulation process, the water vapor will bring impurities generated by chemical corrosion caused in the low-voltage dc applications within hours the film resistor is open. Changing the preferred film thickness of TCR will be severely affected. As the thin deposited layer is more easily oxidized, therefore the rate of degradation of the high resistance thin film resistor is very high.

Precision wirewound chip resistors

  Wirewound chip resistor is generally divided into power wirewound resistors chip resistors and precision wirewound resistor SMD resistor. Power wirewound chip resistor resistor use process will change greatly, not suitable for precision demanding circumstances use。 Accordingly, the present discussion does not consider such a resistor.

  Wirewound resistor production method is generally the insulating resistance wire wound on a specific diameter spool。 Different diameter, length, and alloy material may achieve a desired resistance and initial characteristics. Precision wirewound resistor the higher ESD stability, noise is lower than film or thick-film resistors. Wirewound resistors with low TCR, high stability。

  The wirewound resistors initial error can be as low as ± 0.005%. TCR (temperature change of one degree Celsius, the amount of change in resistance) 3 ppm / ° C typ. However, lower resistance value, the the wirewound resistors general in 15 ppm / ° C to 25 ppm / ° C. Thermal noise reduction can be achieved within a limited temperature range, TCR of ± 2 ppm / ° C。

  Wirewound resistor process, the resistance wire to the inner surface (close to the spool side) contraction, the outer surface of the stretch. This process produces permanent deformation - relative to the elastic deformation or irreversible deformation resistance wire must be annealed. Permanent mechanical changes (unpredictable) will cause any change of the resistance wire and resistance electrical parameters. Therefore, the resistive element electrical performance parameters there is a lot of uncertainty.

  Inductor coil structure, wirewound chip resistors near the number of laps will produce coil capacitance。 To improve the response speed of use, using a special process to reduce inductance。 However, this will increase the costs, but also reduces the effect of the inductor is limited。 Due to the design of inductance and capacitance, wirewound resistors high-frequency characteristics, especially at frequencies above 50 kHz.

Related Searches: chip resistors, chip capacitors, chip inductors, SMD diode

Prev: The SMD capacitor: digital capacitive isolators defined high performance latest reference
Next: No!
Print | Close
Copyright © HONGKONG CHANGWANG GROUP CO., LIMITED  Design:   Admin  Email  
甘肃11选5投注 广西快乐十分走势图 99彩票导航网 新疆11选5投注 陕西快乐十分开奖 陕西11选5走势图 新疆11选5走势图 广西快乐十分走势图 陕西11选5走势图 广西快乐十分