Resistors are considered one of the most critical components in electric circuits. Resistors are an integral part of every power supply system and effectively provide power and prevent short courses. A type of resistor is known as a fixed resistor which is also known by the names ohmic resistors or linear resistors invented by William Stanley. Jr and George Westinghouse. This type of resistor has a fixed value for all of its characteristics and is solid. They have set values of resistance and power ranking at all times.
How Does a Fixed Resistor Work?
A fixed resistor consists of two terminals, aiming to implement electrical resistance similar to a circuit element. The current that flows through this resistor is always directly proportional to the voltage supplied across the two terminals of the resistor. Therefore, this relation can be signified by using Ohm’s law which is:
V = I × R
The V indicates voltage, I indicates current, and R shows resistance. For example, if you connect a resistor of 100-Ohm across a 10-volt potential difference, a current with a value of 0.1 Ohm will pass through the circuit.
Construction of Fixed Resistor
A fixed resistor consists of two main parts. The first is the resistive element which is wire wound into a coil. The second one is the outer casing that can be made of different materials like plastic, ceramic, or even metal, depending on its application. The resistive element is usually designed like a coil so as not to take too much space and increase its surface area.
The resistance of the fixed resistor depends on a few things: its diameter, length, and material properties. You can adjust both the size and diameter during the production process or even after the production by either adding or removing more wires. However, it is hard to change the material properties after the production process, although they can be measured and recorded so that their efficiency can be improved while designing new products of such kind.
Values of Fixed Resistor
The values of fixed resistors can range from 0 to 100 Gigaohms. Fixed resistors are designed in wide varieties and can carry different values. The value of the resistor can be identified through colour bands, which are arranged in sequence from most to the least significant ones. The first two bands will locate the first and second digits, whereas the third digit will always indicate how many zeros need to be added after those two digits. For example, a resistor that consists of red, green, and yellow bands is usually 2700 Ohms.
Colour Code of Fixed Resistor
The colour codes of fixed resistors usually indicate the resistance value of a resistor. As we know, the value of fixed resistors cannot be adjusted once they are installed. Therefore, using these colour bands makes it possible to identify the importance of resistance and then search up the values in a given table.
Fixed resistors usually consist of four-colour bands, and each one of these colours gives a different piece of information. The first two bands represent the resistance value, whereas the third band represents its tolerance. The fourth band is often found on the metal-film resistor. However, they can have a gold stripe or be blank as well.