Different Types of Electrical Resistors
A resistor is a type of electrical component that can provide current resistance, benefitting electronic circuits of all types. With a resistor, current flow may be reduced, signal levels can be adjusted, voltages may be divided, and much more. As such, resistors are extremely common for the protection of electrical networks and electronic equipment. Depending on the application, there are a variety of resistor types that may be used, each providing their own unique benefits for various applications.
Fixed resistors are electrical resistors in which ohmic values remain at a constant level during operation, and the two major types are carbon film and metal film resistors. The carbon composition resistor may either be a solid or film type, both not requiring any substrate for their functionality. With solid type carbon resistors, a mixture of grounded graphite is used to provide resistive properties, and carbon and resin are mixed and molded together in order to create a rod. To adjust the component’s resistance capability, the values of the composition may be adjusted. Once the rod has been pressed, copper lead wires are attached and encapsulated, and a varnish protective coating is applied.
With film type carbon resistors, a carbon film is placed on an insulating substrate through thermal decomposition. When the resistor is produced, the resulting film is very thin, thus precise control of the thickness is needed in order to change its resistance value. To create an electrical connection, low resistance electrodes are applied to the film, and metal caps with integral leads are pressed against them. Generally, carbon composition resistors serve well for general purpose circuits, benefitting both high frequency and stability circuits.
When implementing a resistor in a system that requires high frequency performance and reliability, the metal oxide resistor often proves much better than carbon resistors. Metal oxide resistors are composed of tin and antimony oxides that are fused onto a substrate, and their films are often extremely thin. To create rods for the resistor, glass is melted and shaped, or a ceramic substrate may be used. Spiraling of the materials is used to create its resistance values, and the finished rod may be cut to size the component. Once the rod has been fitted with end caps, an epoxy coating is implemented for protection.
Metal film resistors serve as the other major type of electronic resistor, and they are typically constructed from nickel-chromium alloys for their film. As compared to other types of resistors, such as the thin film resistor, materials may be placed utilizing varying techniques. Resistance values are also adjusted through cutting helixes through resistor coating, rather than using etching methods as is seen in other resistors. As a result, metal film resistors have decent tolerances and temperature coefficients. For applications, they provide low noise and non-linearity as well, allowing for them to be useful for various electronic applications.
The wirewound resistor is a type of metal film resistor, and they are dictated by wires wrapped around a ceramic substrate. The wires of such electronic resistors are composed of nichrome which allows for them to have a high value of resistivity and stability as compared to carbon materials. Due to this resistance capability and their stability, wirewound resistors are most often used for applications that require accuracy such as precision instruments.
With the protective properties of resistors, having them for your electronic systems and applications is crucial for safe operations. At AFR Enterprises, we can help you secure the fixed resistors and other electronic resistors that you need from top electrical resistor manufacturers. Explore our robust electronic catalogues at your leisure, and our team of industry experts is readily available 24/7x365 to provide you with rapid lead-times and competitive pricing on all that we carry. Get started today and see how we can help you fulfill all of your operational needs with ease.