Different types of resistors and their applications

There are various types of resistors out there, but fixed resistors have resistances that only change slightly with temperature, time, or operating voltage. the variable resistors are used to adjust circuit elements such as volume control or a lamp dimmer. Also, it is used as a sensing device for heat, light, humidity, force, chemical activity, etc. Resistors are great electrical components used to reduce current flow, adjust signal levels, divide voltages, bias active elements, and other uses. It is a passive two-terminal electrical component that implements electrical resistance as a circuit element. High-power resistors are designed to dissipate many watts of electrical power as heat, may be used as part of motor controls, in power distribution systems, or as test loads for generators. There are various types of resistors out there, but fixed resistors have resistances that only change slightly with temperature, time, or operating voltage.

types of resistors

Today You’ll get to know the various types of resistors and their advantages and disadvantages

Contents

Types of resistors

The common types of resistors are categorized into fixed and variable resistors.

Fixed resistors:

Fixed resistors are the most common and widely used types of resistors. They are used in electronic circuits to set the right conditions, and their values are known during the design phase of the circuit. Also, they never require to be changed to adjust the circuit, just as their name has indicated. There are many other types of fixed resistors that will be discussed below.

Fixed resistors

Variable resistors:

These types of resistors are designed with a fixed resistor element and a slider that taps into the main resistor element. This makes the component achieve three connections; two connections to the fixed element and the third is the slider. In this manner, it acts as a variable potential divider if all three connections are used. It is possible to connect to the slider and one end to provide a resistor with variable resistance.

Carbon film preset potentiometer Variable resistors and potentiometers are used for all forms of control. Starting from the volume controls on radios to sliders in audio mixers to a lot of areas where variable resistance is needed. On the other hand, a potentiometer and variable resistor strictly a potentiometer is a component where fixed resistors that have a slider are employed to provide a potential division from the voltage at the top. This is the same with a variable resistor, but the slider linked to one end of the resistor helps to provide a true variable resistance.

variable resistors

Other types of resistors

The majority of resistors are standard fixed resistors or variable resistors. There are other kinds of resistors that are used in some specialized applications such as light-dependent resistor/photoresistor, Thermistor, varistors, etc.

Light-dependent resistor / Photoresistor:

These types of resistors are also known as LDR or photoresistors as they change their resistance with the level of light. They are mostly used in sensor applications and they provide a very cost-effective solution in most cases. Normally, a leaded light-dependent resistor has a lag in the time taken to respond to light changes. However, they are cheap and easy to use.

light dependent resistor LDR

Thermistor:

The thermistor is a heat-sensitive resistor whose resistance changes with temperature. Some are designed with a negative temperature coefficient, which is known as the NTC thermistors. Other designs have a positive temperature coefficient, PTC thermistors.

thermistor

Varistor:

These types of resistors are available in various forms. Their resistance varies with the applied voltage and as a result, they find uses for spike and surge protection. Often, they are described as Movistors gotten from the words Metal Oxide Varistors. The selection of leaded varistors is the device that is used in surge or transient protected mains extension leads. It is also used to protect computers. Note that whenever a varistor receives a spike, its properties change slightly.

Understanding varistors

Types of fixed resistors

Below are the various types of fixed resistors available.

Carbon composition:

These types of resistors are very common and are one of the oldest versions. Although there are newer forms that provide a better performance, cheaper and smaller. Carbon composition resistors are created from carbon granules with a binder then made into a small rod. This resistor suffered from a large negative temperature coefficient and large and erratic irreversible changes in resistance due to heat or age. This granular nature of carbon and binder also results in noise being generated when current flows. With these limitations, I guess there are better options.

carbon composition resistor

Carbon film:

The carbon film resistors were introduced during the early days of transistor technology when power levels tended to be lower. These types of resistors are produced from cracking hydrocarbon material onto a ceramic former. The carbon film is protected either by a conformal epoxy coating or a ceramic tube. The deposited film results in resistance set by cutting a helix into the film. Thus, the resistors are highly inductive and have little use in most RF applications. They exhibited a temperature coefficient of between -100 and -900 parts per million per degree Celsius.

carbon film resistors

Metal oxide film resistor:

These types of resistors are currently the widely used form of a resistor. Instead of a carbon film, a metal oxide film is deposited on a ceramic rod. The film is protected by using a conformal epoxy coating, and it has a temperature coefficient of around + or – 15 parts per million per degree Celsius. This makes it superior in performance to that of any carbon-based resistor. Furthermore, metal oxide film resistors can be supplied to a much closer tolerance, 5% or 2% being standard, 1% are also available. Much lower noise is also produced than carbon resistors.

metal oxide film resistor

Metal film resistor:

The metal film resistors are very similar to metal oxide film resistors. They look alike visually and in performance, they are quite comparable. A metal film is deposited on a ceramic rod instead of a metal oxide film. Metals such as nickel alloy may also be used. They are used when a leaded resistor is required.

metal film resistors

Wire wound resistor:

These types of resistors are designed generally for high-power applications. they are made by winding wire with a higher-than-normal resistance wire on a former. They are wounded on a ceramic former and may be covered by a vitreous or silicone enamel.

Wire wound resistors are suited to high powers and exhibit a high level of reliability at high powers. It is achieved along with a comparatively low level of temperature coefficient, although it depends on the former, wire used, etc. Because wire wound resistors are intended for high power applications, they are designed so that they can be mounted onto a heatsink so that the power is dissipated onto metalwork to carry it away.

Wire wound resistors are not suitable for operation above low frequencies, although by winding parts of the resistance wire in different directions the inductance can be reduced somewhat.

wire-wound-resistor-

Surface-mount resistors:

The surface mounts technology which is also known as the SMT is now the major format used in electronic components today. They are less complex in automated manufacturing, and they can provide very high levels of performance. SMT resistors utilize similar tech to other forms but in a surface mount format.

construction and diagram of smd resistors

That is all for this article where the various types of resistors have been discussed. I hope you get a lot from the reading, if so, kindly share with other students. Thanks for reading, See you next time!

Different types of resistors