Name three types of fixed resistors.
The correct answer and explanation is :
Correct Answer:
Three types of fixed resistors are:
- Carbon Composition Resistors
- Metal Film Resistors
- Wire-Wound Resistors
Explanation (300 Words):
Fixed resistors are electronic components with a set resistance value that does not change with temperature, voltage, or time under normal conditions. They are widely used in circuits to limit current, divide voltages, and bias active elements. The three common types of fixed resistors each have unique characteristics that suit them to particular applications.
1. Carbon Composition Resistors:
These resistors are made from a mixture of carbon powder and a binding resin. The mixture is shaped into a cylindrical form and enclosed in a plastic case. Carbon composition resistors were once very common due to their simplicity and low cost. They can withstand high energy pulses, making them suitable for surge-sensitive circuits. However, they have relatively poor stability, higher noise levels, and wider tolerance ranges (±5% to ±20%), making them less ideal for precision work.
2. Metal Film Resistors:
Metal film resistors are manufactured by depositing a thin layer of metal (like nickel-chromium) onto a ceramic rod. The resistance value is adjusted by cutting a helical groove in the film. These resistors offer high accuracy, low noise, and excellent long-term stability. Their tolerance can be as tight as ±0.1%, and they have a low temperature coefficient, making them ideal for precision electronic devices such as instrumentation, measuring equipment, and audio applications.
3. Wire-Wound Resistors:
Wire-wound resistors are made by winding a metal wire (typically nichrome) around a ceramic or fiberglass core. They are known for their durability and high power dissipation capability. These resistors are especially suited for applications involving high current or power, such as power supplies and motor controllers. However, their inductive nature makes them unsuitable for high-frequency applications.
Each of these resistors serves specific roles in electronic systems based on their unique electrical and physical properties.