Why Transistors Aren’t As Bad As You Think
Everything You Need to Know About Wirewound Resistors
The current market is rich in power resistors for your choosing. If you are wondering about wirewound resistors, you should know that they are one of the oldest types of resistors that are used and sold in the market. The construction of all kinds of wirewound resistors is more or less the same. Around the core of an insulating material, a metallic wire will then be winded. Despite the fact that they are created in the same manner, you can expect variations in the application of the different types of resistors. You can group wirewound resistors into two types. You have precision wirewound resistors and power wirewound resistors. Again, each of these resistors has their own functions. 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. Since these resistors are very accurate, their tolerance levels should be under one-tenth percent. In terms of temperature coefficient, precision wirewound resistors are better with 5 ppm/C than with most metal film resistors with 25 ppm/C. With values such as 30 ppm, their stability is fairly good for twelve months of alteration and functioning at full power rating. If you require a resistor for temperature increases below 30C, then this is the kind of resistor for you. When you look at these wirewound resistors, they are coated by epoxy materials for this reason alone.
For the other type of wirewound resistor, you call them power wirewound resistors. Their power range is between 0.5 watts to 1000 watts. The coating type of these power resistors is one way for you to categorize them. When the lowest dissipation ranges, you have to go with silicone resins. These resistors are small and can endure temperature increases up to 300C above their normal levels. Another kind of power wirewound resistors is the one that has a porcelain enamel coat. This is a coating type that provides good insulation properties when there are low temperatures. You can expect the insulation to be less when the temperature goes up. This is one of the reasons why this kind of resistor is less common. The maximum operating temperature for this kind of coating is 400 degrees. Their resistance values range between 0.1 and 10 kOhm.
You have another coating type for power wirewound resistors, and they are ceramic coating. This is considered as the standard type of power wirewound resistors. From these resistors, you will see that they have a ceramic coating and core to provide wire protection. When it comes to this coating, it can maintain good insulation properties while ensuring to have effective energy dissipation. Furthermore, its physical protection is also good. You have a power rating from 5 to 18 watts for this kind of resistor. Without any problem, this kind of resistor can warm up around three hundred degrees. In terms of resistance, you can expect them to be between 10 and 20 kOhm.