Metal Foil Resistor is an  important part of Microhm Electronics' product linup. We offer surfact mount type, like NMS2818,NMS4527,NSR series and MPR series, as well as radial type, including To247 type resistor, To218 type resistor and MVR series. The excellent properties for precision and stability are due to a combination of several characteristics, which are following from the design principles of the metal foil resistor.
 
Foil resistors achieve a low TCR by taking advantage of two characteristics of the foil. The resistance of the foil naturally increases as temperature increases. The resistor is manufactured so that rising temperature causes compression of the foil. This makes the resistance drop as temperature rises. The total effect is one of very little resistance change as temperature changes.

 
Resistive tolerance tells how close to the nominal value of resistance an actual resistor will be. For example, a company may sell resistors that are advertised to be 100 ohms with a tolerance of 1 percent. This means that the actual value of one of these resistors may range from 99 ohms to 101 ohms. Foil resistors can be made to have tolerances as low as 0.001 percent.
 
Resistors, especially wirewound resistors, can introduce inductance and capacitance in to a circuit. This can change the way the circuit responds to changes in frequency and can distort pulses as they pass through the resistor. Foil resistors are internally shaped especially to minimize this effect.

 
Stability of load life  is a measure of how well the resistor maintains a constant resistive value over time as it used under varying loads and temperatures. Due to their construction foil resistors are very stable in this respect.