The most often used resistors in electrical circuits are fixed resistors. The resistance of these resistors is fixed. As a result, the fixed resistor’s resistance cannot be changed.
Fixed resistors are those whose resistance does not vary when voltage or temperature changes. Fixed resistors come in a variety of tools, forms and sizes.
In all situations, an ideal adalm2000 fixed resistor maintains a constant resistance. The resistance of actual resistors, on the other hand, fluctuates somewhat as temperature rises.
100K, 10k, 100, and 10 are the most often used fixed resistor resistance values.
Fixed resistors are more expensive than variable resistors since we have to buy a new fixed resistor every time we want to modify the resistance. We utilize a single variable resistor for varied resistance levels when using variable resistors. The ammeter is used to measure the resistance of the fixed resistor.
Resistance definition of Fixed Resistors
After a thorough examination, the resistor values for a certain application are chosen. 1/4W resistors with a 5% tolerance carbon content or carbon film resistors are utilized in most ordinary circuits. Wire-wound, ceramic, and metal alloy resistors are extensively utilized in power applications.
The resistance is chosen to be at least twice the anticipated power dissipation. If a resistor is being used for power, it should be at least three or four times larger than the predicted power dissipation value.
When choosing a resistor for a commercial or professionally constructed circuit, the designer must take into account a number of additional factors. It may entail examining and analyzing the datasheets given by the resistor manufacturer.
Resistors come in a variety of shapes and sizes for use in the electronics sector. The Worldwide Electrotechnical Commission (IEC) is a non-profit organization that develops and publishes international standards for all electrical, electronic, and related goods, including resistors. The E series has the following resistors: E3, E6, E12, E24, E48, E96, and E192.
Standard resistances in the E12 series, for example, are 10, 12, 15, 18, 22, 27, 33, 39,….till 10M. The numbers in the range are chosen to follow an exponential curve, and the error will be within a specified percentage if you substitute your computed value with one from the recommended range. Some resistors have the values or ratings printed with numbers or letters on the bodies, while others have the values printed with numbers or letters on the bodies.
Types of fixed resistors
The different types of fixed resistors include: Metal oxide film resistor, Foil resistor, Carbon film resistor, Wire wound resistor, Metal film resistor, Carbon composition resistor and Metal glaze resistor.
Metal oxide film resistor
The metal oxide film resistor is a form of passive component in which a resistive element made of metal oxide film is used to limit the flow of electric current to a specific level.
Metal oxide film resistors are virtually identical to metal film resistors in terms of construction. The only variation is the type of material utilized to make the film. Metal film resistors use metals such as nickel and chromium to create the film, whereas metal oxide film resistors use metal oxides such as tin oxide to create the film.
Metal oxide film resistors are less expensive than carbon composition resistors. These resistors are used in high-temperature applications.
Foil resistors are the most precise and reliable components for limiting the passage of electric current to a specific level. When compared to other types of resistors, foil resistors emit less noise. High precision resistors are another name for these resistors. The TCR (Temperature Coefficient of Resistance) of foil resistors is low.
Carbon film resistor
In electrical circuits, carbon film resistors are the most often used resistors. Carbon film resistors are created by applying a carbon film on a ceramic substrate. The carbon layer works as a resistive element to the electric current, while the ceramic substrate serves as an insulating medium.
Both ends of the resistive element are equipped with metallic end covers. Copper leads are connected at two ends of these end caps. Compared to carbon composition resistors, carbon film resistors emit less noise.
Wire Wound resistor
Wire Wound resistors are passive components that are manufactured by wrapping metal wire around a metal core. To the electric current, the metal wire serves as a resistive element. As a result, the electric current is limited by the metal wire. The non-conductive substance is the metal core. As a result, electric current cannot pass through it.
Metal wires made of manganin or nichrome are commonly employed because they have a high resistance to electric current.
Types of wire wound resistors
There are 2 types of Wire Wound Resistors: Precision wire wound resistor and Power wire wound resistor. The detailed information about Wire Wound Resistors types are following.
Precision Wire Wound Resistor
Precision wire wrapped resistors work with excellent precision at low temperatures. Because of its excellent accuracy, it is utilized as a precision resistor in instrumentation.
Power wire wound resistor
Power wire wound resistors that work at high temperatures are known as power wire wound resistors. This type of resistor is frequently utilized in high-power applications.
Metal film resistor
Metal film resistors are passive components that employ metal film to limit the passage of electric current to a specific level. Metal film resistors are virtually identical to carbon film resistors in terms of manufacture. The only variation is the type of material utilized to make the film. The film in carbon film resistors is made of carbon, whereas the film in metal film resistors is made of nickel, chromium, or tin and antimony.
TCR is low in metal film resistors (Temperature Co-efficient of Resistance). TCR refers to the rate at which a material’s resistance changes as the temperature rises.
Carbon composition resistor
A carbon composition resistor is a passive component that limits the passage of electric current to a certain level.
A cylindrical resistive element with integrated metal end caps is used to make the carbon composition resistors. The carbon composition resistor’s cylindrical resistive element is constructed of a blend of carbon powder and ceramic. The carbon powder is an excellent conductor of electricity.
In the 1960s and before, carbon composition resistors were the most often utilized resistors. However, due to their exorbitant cost and lack of stability, these resistors are rarely utilized nowadays.
Metal glaze resistor
The metal glaze resistor is a passive component that uses a combination of glass powder and metal particles to limit the flow of electric current to a specific level.
TCR is low in metal glaze resistors (Temperature Co-efficient of Resistance). TCR refers to the rate at which a material’s resistance changes as the temperature rises.
In conclusion, the most common resistor is a fixed resistor. When people refer to a resistor, they are almost always referring to a fixed resistance. The axial carbon film resistor, seen to the right, was the most popular form on earlier printed circuit boards (PCBs) that employed through-hold components. The resistance of fixed resistors is always the same. Fixed resistors are made of several resistor materials. Materials have an impact on resistor attributes such as tolerance, cost, and noise for all resistor types. Axial and SMD packaging are offered for fixed resistors.