Resistors are among the most basic and common electronic components. As the name suggests, their job is to “resist” the flow of current. They are passive devices that contain no power source, but simply reduce voltage or current by converting it to heat energy as electrons flow through them. Resistors can be used in voltage-to-current or current-to-voltage converters, and they can be connected in series or parallel to form networks. They are many different types of resistors on the market. Here is what you should know.
The individual characteristics of a resistor affect the amount of resistance it provides, as well as its suitability for specific applications. Important characteristics include:
Depending on their characteristics, individual resistors have resistance values ranging from less than a single ohm to tens of millions of ohms. A fixed resistor has only a set resistance value, while a variable resistor has an infinite number of possible resistance values from zero to its maximum value.
Today’s fixed value resistors fall into one of four broad types:
Composition Resistors: Made of carbon dust or graphite bound with non-conductive ceramic clay, these resistors are inexpensive and general-purpose in nature. The ratio of conductive dust to insulating ceramic determines the overall resistance. These low- to medium-power resistors have a low inductance, but they can suffer from stability and noise issues when hot.
Film Resistors: Made from conductive metal oxide paste deposited onto an insulating ceramic substrate, film resistors are laser cut into a precision spiral helix. This makes them ideal for applications that require very tight tolerances. Film resistors may be “thick-film” or “thin-film,” depending on the thickness of the paste layer, which affects the resistive value. Film resistors can achieve an ohmic value of 10 million ohms. They are ideally suited to high frequency or radio frequency applications, due to their temperature stability and lower noise.
Wire-wound Resistors: Wire-wound resistors are made by winding a thin metal alloy wire onto an insulating ceramic. They have high-precision low ohmic values and high power ratings, making them ideal for heat sinks and measuring circuits. Some wire-wound resistors have inductance as well as resistance, providing a combined effect known as impedance.
Semiconductor Resistors: Semiconductor resistors are formed in silicon or another semiconductor substrate. Unlike traditional resistors, semiconductor resistors increase in conductivity as temperature rises. They are extremely useful in high frequency precision applications.
Here at Quest Components, we are committed to providing you with the information you need to help your business continue to run smoothly. An ISO 9001:2015 Certified Company headquartered in Industry, CA, Quest Components specializes in passive and active board level components. We also provide a variety of services to OEMs (original equipment manufacturers) and CEMs (contract electronics manufacturers) across the globe. Contact Quest Components today at 626-333-5858 for all your electronic component needs!
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