A fixed resistor has a specific, unchangeable resistance value that is determined during its manufacturing process. These resistors are designed to provide a stable resistance value and are commonly used in circuits where a consistent resistance is required, such as voltage dividers, current limiters, and signal conditioning. Once installed in a circuit, a fixed resistor’s resistance value cannot be adjusted or varied.
The main difference between a fixed resistor and a rheostat lies in their intended use and design. A rheostat is a type of variable resistor that is specifically designed to adjust resistance manually. It consists of a resistive element with a sliding contact (wiper) that can move along the resistive track. By adjusting the position of the wiper, the resistance between the wiper and one end of the resistor can be varied, allowing for fine control over the resistance in a circuit.
To determine if a resistor is fixed or variable, you can visually inspect the resistor and its construction. Fixed resistors typically have two leads or terminals and are enclosed in a cylindrical or rectangular body with color bands indicating their resistance value. They do not have any moving parts or adjustments. In contrast, variable resistors like rheostats or potentiometers will have an additional terminal or a sliding contact (wiper) that can be adjusted to change the resistance value.
The difference between a variable resistor and an adjustable resistor lies in their construction and usage. A variable resistor, such as a rheostat or potentiometer, allows for manual adjustment of the resistance within a specified range using a movable contact (wiper). This adjustment can be made to vary the resistance in a circuit as needed. An adjustable resistor, on the other hand, refers to a resistor whose resistance value can be adjusted or set during the manufacturing process or through external means (such as trimming resistors with a screwdriver). Adjustable resistors are typically fixed once set and do not allow continuous manual adjustment like variable resistors.
Constant resistance refers to a resistor that maintains a stable and unchanging resistance value regardless of external conditions such as temperature or applied voltage. Fixed resistors are examples of components that exhibit constant resistance. Variable resistance, on the other hand, refers to a resistor whose resistance value can be adjusted or varied. This adjustment can be manual (using variable resistors like potentiometers or rheostats) or automatic (as in the case of sensors or devices whose resistance changes with external factors like light or temperature). Variable resistance provides flexibility in adjusting circuit parameters, while constant resistance ensures stability in circuit operation under varying conditions.