What Type of Resistors Can Only Have One Ohmic Value?

Resistors are electrical components that resist the flow of current in a circuit. They come in various types and values, but not all resistors can have only one ohmic value. In this article, we’ll explore the types of resistors that can only have one ohmic value.

Fixed Resistors

Fixed resistors are the most common type of resistor and they have a fixed resistance value that cannot be changed. These resistors come in different packages such as through-hole, surface mount, and chip resistors. Fixed resistors are used in many electronic circuits where a specific resistance value is required.

Fixed resistors can only have one ohmic value because their resistance is determined during manufacturing by selecting specific materials, dimensions, and tolerances. Once manufactured, the resistance value cannot be changed or adjusted.

Carbon Composition Resistor

A carbon composition resistor is another type of fixed resistor that has only one ohmic value. This type of resistor is made from carbon particles mixed with a binder material and molded into a cylindrical shape. The ends of the cylinder are then coated with metal caps to make electrical connections.

Carbon composition resistors are inexpensive but not very precise compared to other types of fixed resistors. They also tend to drift over time due to changes in temperature and humidity.

Metal Film Resistor

Metal film resistor is another type of fixed resistor that has only one ohmic value. This type of resistor is made by depositing a thin film of metal onto a ceramic substrate or plastic film. The thickness and length of the metal film determine its resistance value.

Metal film resistors are more precise than carbon composition resistors and have better stability over time. They also have lower noise levels and higher power ratings compared to carbon composition resistors.


In conclusion, there are several types of fixed resistors that can only have one ohmic value including carbon composition and metal film resistors. These types of resistors offer different advantages depending on their application requirements such as cost-effectiveness or precision.

When selecting a resistor for your electronic circuit design, it’s important to consider factors such as tolerance, stability over time, noise levels, power ratings, and cost-effectiveness among others.

Remember that choosing the right type of resistor for your project can make all the difference in achieving optimal performance and reliability.


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