Everything You Need to Know About Wirewound Resistors
The current market is rich in power resistors for your choosing. Wirewound resistors are among the oldest types of resistors but are still used in the current market. The construction of all kinds of wirewound resistors is more or less the same. Usually, a metallic wire is winded around the center of an insulating material. Though its creation is similar across types, their areas of application are different. Wirewound resistors can be classified into two accordingly. These are precision wirewound resistors and power wirewound resistors. The applications for these wirewound resistors are many. They can be used for current and temperature sensors.
Some of the most common applications of precision wirewound resistors include measuring bridges and accurate calibration devices. Under one-tenth percent should be the tolerance of these very accurate resistors. Their temperature coefficient is about 5 ppm/C, and this is always better than what most metal film resistors can give you which is about 25 ppm/C. Their stability is fairly good where their values of 30 ppm alterations function at full power rating for twelve months. This is the kind of wirewound resistor that you need if you will be requiring temperature increases below 30C. For this reason alone, these wirewound resistors are often coated with epoxy materials.
Another kind of wirewound resistor is the power wirewound resistors. Between 0.5 watts and 1000 watts is the range of power of these wirewound resistors. If you want to break down these power resistors by kind, you have to do so according to their coating type. For purposes that require the lowest dissipation ranges, silicone resins are the most common. They can withstand temperature increases that are 300C above normal levels and are small resistors. Another type of power wirewound resistors is coated with porcelain enamel. This kind of coating is widely used for providing good insulation properties at low temperatures. If the temperature goes up, the insulation will considerably be less. That is why this makes these resistors less common. 400 degrees is basically the maximum operating temperature for this type of coating. If you talk about their resistance values, they are within 0.1 and 10 kOhm.
Another coating type for power wirewound resistors is ceramic coating. This is the standard type of power wirewound resistor that is used. From these resistors, you will see that they have a ceramic coating and core to provide wire protection. This coating provides an effective energy dissipation while still making sure that it has good insulation properties. Moreover, you get good physical protection with it. Their power ratings range between 5 and 18 watts. Even while warming up around three hundred degrees, this resistor will not have any problems at this range. In terms of resistance, you can expect them to be between 10 and 20 kOhm.