Common Types of Resistors
Resistors are commonplace components for countless electronic components, coming in the form of passive components that impede the flow of current within electrical circuits. Resistors can come in numerous forms, many featuring varying designs and characteristics that allow them to take on differing roles. Depending on the resistor, one may use such components for dividing voltages, generating heat, controlling gain, terminating transmission lines, and much more. To familiarize yourself with resistors, we will provide a brief overview of the most common types.
Fixed resistors are the most widely used variation, featuring resistance values that stay constant during varying conditions. To affect their exact resistance value, noise, tolerance, and other characteristics, different materials may be used for construction. Generally, the most common types of fixed resistors include those such as wirewound, carbon composition, cermet oxide, metal oxide, thin film, thick film, fusible, carbon film, and metal film resistors.
Wirewound resistors are current limiters, constructed through the winding of a conductive wire around a non-conductive core. The conductive wire is what determines resistance values, and its thickness and alloy type will allow for control. Generally, wirewound resistors find use in fuses, circuit breakers, and other high power applications.
Carbon Composition Resistors
Carbon composition resistors are an older form of fixed resistor, allowing for current to be managed and reduced to a preset level. Generally, such components feature resistance values ranging from 1 ohm to 22 Mega ohms, and they typically find use in welding controls and power supplies.
Metal Film Resistors
Metal film resistors are a type of axial resistor, and their design features a thin metal resistive element that is placed over a non-conducting body. With high tolerance, ease of maintenance, and the ability for manual operation, such resistors find use in various high-frequency applications related to communications and instrumentation. Additionally, their stable performance, low weight, high precision, and other optimal factors make them well suited for some military aerospace systems.
Unlike fixed resistors, variable resistors are capable of adjusting resistance values. Generally, this is carried out through the presence of a rotating shaft and wiping contact, allowing for resistance to be changed as the contact shifts. For their types, variable resistors come in the form of rheostats, potentiometers, and trimmers.
Rheostats primarily serve for current control, capable of adjusting resistance without break. Utilizing two terminal connections, one is attached to the resistive element while the other connects to the sliding contact. Similar in winding to a wirewound resistor, current will travel across the rheostat and adjustments to resistance are made by modifying the positioning of the wiper. Typically, rheostats are used for light intensity, motor speed, and oven controls.
While the rheostat utilizes two terminal connections, the potentiometer utilizes three. Generally, various materials are used for the construction of such devices, those of which include carbon composition, metal film, wirewound, cermet, and conductive plastics. Operating similarly to a changeable voltage divider, two terminals are attached to each end of a resistive element while the last terminal is connected to the wiper. As the wiper is adjusted across the resistive element, the amount of resistance that the potentiometer exhibits will change. As such, they commonly serve applications related to audio volume control applications and similar systems.
Trimmers are variable resistors that feature an extra screw, allowing for resistance to be changed with screwdriver adjustments. Constructed from carbon film, carbon composition, cermet, and other wire materials, such devices operate in a range of 50 Ohms to 5 Mega ohms. Furthermore, their power ratings range from ? Watts to ¾ Watts.
Alongside such examples, there are numerous other types of resistors that one may use for managing current within electrical circuits. AFR Enterprises is a leading supplier of resistors, providing customers access to a plethora of electronic components that have been sourced from leading manufacturers that we trust. With our AS9120B, ISO 9001:2015, and FAA AC 00-56B certification and accreditation, we guarantee top quality electronics that you can steadily depend on with ease. Take the time to explore our vast offerings, and our industry experts are always on standby to assist you throughout the purchasing process however necessary. At AFR Enterprises, we are your strategic sourcing partner for all your operational needs.
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