Past two decades, the electronics industry at an alarming pace. New technological advances in reducing equipment size, but also increase the discrete device manufacturers to develop the ideal performance of the pressure. 

    In these devices, always maintain a high chip resistance of the current demand, and is the basis of many circuit components. Their utilization of space than discrete package resistance, reducing the workload of the assembly preparation. With the popularity of the application, chip resistors have an increasingly important role. The main parameters include ESD protection, thermal electromotive force (EMF), thermal resistance coefficient (TCR), self-heating, long-term stability, power factor and noise. 

     Contrast the following techniques will be discussed in precision wire wound resistor circuit applications. Note, however, there is no chip-type wire wound resistor, therefore, subject to weight and size restrictions require the use of precision chip resistors for the application of the use of this resistance. 

    Although each component or subsystem can be upgraded to improve overall performance, but overall performance is still short by the component chain board decision. Each system component has a bearing on the overall performance of the inherent advantages and disadvantages, especially short-term and long-term stability, frequency response and noise problems. Discrete resistors industry around the resistance line, thick film resistors, thin film resistors and metal foil resistor technology has made progress, but the performance from the unit cost considerations, each resistor has a number of factors need to be weighed.

     Advantages and disadvantages of a variety of resistance techniques as shown in Table 1, the table gives the thermal stress and mechanical stress on the resistance of the electrical characteristics. 

Table 1: characteristics of different types of resistance 

    Stress (both mechanical stress or heat stress) can cause the electrical parameters of resistance to change. When the shape, length, geometry, configuration or modular structure by mechanical or other factors change, the electrical parameters will change, this change can be used to represent the basic equation: R = ρ L / A, where 

R = resistance, in ohms,

ρ = resistivity to Oumu Mi as a unit,

L = length of the resistive element, in meters,

A = cross-sectional area of ​​the resistive element, in m2. 

      When the current through the resistive element to generate heat, thermal reaction causes the device to each of the material to swell or shrink mechanical changes. Ambient temperature conditions will produce the same result. Therefore, the ideal resistive element based on these natural phenomena should be able to self-balance, in the resistance process to maintain the physical consistency of the course do not have to compensate for thermal effects or stress effects, thereby improving system stability