Continuing on the types of resistors and where each one shines, let’s look at a few more variations of resistors.
Metal Film Resistor: They are similar to carbon film resistors except a metal film is deposited instead of carbon on a ceramic core. The usual material is nickel chromium. Similar to carbon film they have great precision. Where it shines is in the thermal stability over wide temperature ranges.
Thick Film Resistor: Created by applying a thick paste of conductive material onto a ceramic substrate using the same techniques we use in making T-shirt prints via screen printing. These are the most common resistors you find in SMD resistors and are dirt cheap. The coating thickness would be around 100um(Hence “Thick” film). The only drawback is that you might not get very low resistance values.
Thin Film Resistor: Similar to thick film resistors but use a thinner layer(0.1um) of conductive material. They provide higher precision and lower resistance ranges in manufacturing. The thin layer formed on the ceramic core is created by using vapour deposition. Laser trimming is done to adjust the values post-deposition.
Metal Oxide Resistor: Made by coating a ceramic rod with a layer of metal oxide (typically tin oxide), these resistors are highly durable and can handle high temperatures. Useful in industrial and high-power applications.
Metal Foil Resistor: They are the most precise and stable types of resistors available in the electronics industry. The core element of a metal foil resistor is an extremely thin layer of resistive metal alloy. Metal foil is etched into a specific resistive pattern using photolithography and then laser trimmed to get precision. They are known to get tolerances of ±0.001% range. They have a fast thermal response to changes in temperature and is known for minimal drift in value even after years of use. But they are expensive.
These are the resistor types I found. As a designer, relying on datasheets is often enough to select the resistor, but understanding resistor evolution helps you see why & where each type excels.
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