Wirewound resistors, like all other resistors, are passive electronic components that limit current. The resistor structure is a metal wire wrapped around a core of non-conductive material.
What is the advantage of a wire wound resistor?
The main advantages of wirewound resistors are that they are more resistant to heat due to their insulating structure. Thus, they are less affected by temperature changes in their environment. They can be used in high temperature environments.
Wirewound Resistor Structure
When wirewound resistors are considered, the types in TH structure may first come to mind, but there are also wirewound resistors in SMD structure.Therefore, the resistive materials used in their structures vary.
Which materials are wirewound resistors made of?
Copper
Silver
Nickel Chromium
Iron Chromium
Aluminum
Iron Chromium
In the following table the properties of the most common alloys are given.
What is the high frequency effect on wirebound resistors?
Wirebound resistors can show inductive and capacitive effects in high frequency applications due to their structure. AC voltage applications are most likely to see this effect. Since there is no frequency in DC voltage applications, this effect is generally not expected to be seen.
Types of Wirewound Resistors
Wirewound resistors have many different uses. Here are some of the different types of wirebound resistors that can be used for different applications:
Precision wirewound
Precision wirebound resistors are manufactured with very low tolerances. For this reason, they are often used in situations where the stability of the resistance value is critical, such as measuring calibration equipment. Usually tolerance values are less than 0.1%. The rate of change of the resistance value with temperature is very low. In general, this value can be evaluated as 5ppm/° C.
Power wirewound Resistors
Power wirewound Resistors emit heat on themselves depending on the current flowing through them. If the amount of current planned to pass in the design to be made is not compatible with the amount of heat that the resistor to be used can emit, the resistor used becomes unusable after a certain period of time. In addition, in some applications, resistors can also be used to increase the temperature of the environment in which the circuit is used due to their heat dissipation properties. Power wirewound resistors can be insulated with special coatings or aluminum armor. Thus, they can be used at very high powers.There is a TCR value for each resistor and this value shows how sensitive the resistor is to temperature change. For power wirebound resistors, the TCR value should be very low. Potentiometer
Potentiometer wirebound resistors usually have 3 terminals and the resistance value can be changed manually. It works as a resistance divider between the 3 terminals in its structure.
Wirebound Resistor Application Areas
As mentioned separately in each sub-heading, wirebound resistors can be used in many different areas. These include heating electronic boards, circuit structures that require precise measurement, electronic circuits that need to perform better against temperature changes, manually changing the resistance value, protecting against voltage fluctuations that may be encountered at circuit inputs.
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