What to Consider When Selecting a Resistor?

What to Consider When Selecting a Resistor

Resistors are passive electrical components required for use in the design and manufacture of many different applications and appliances. Below is a guide to understanding the different types of resistors and how to go about selecting the right one for your project.

What are resistors?

Resistors are electrical components with the power to divide voltage, limit current, and support timing applications. They are passive electrical components that complement various active components, such as integrated circuits or op-amps. There are many different types of resistors to choose from, each with their own pros and cons and unique applications.

Understanding the types of resistors

When it comes to composition, there are three main types of resistors, namely carbon-film resistors, carbon-composition resistors, and metal-film resistors. However, these passive electrical components can be categorized in many other ways, such as by function. In this instance, you would have precision resistors, fusible resistors, power wire-wound resistors, and more.

Carbon-film resistors are known to be more durable than carbon-composition resistors because they are less sensitive to wear and tear and changes in temperature. They also generate less noise internally and are known to have tighter and lower tolerances.

Having said that, most electrical engineers will agree that metal-film resistors are the best choice for maximum performance.  They boast all the benefits of carbon-film resistors, with the added advantage of more accurate resistance values.

How to choose the right resistor?

When choosing a resistor, you will need to look at how it is measured. Resistors are usually measured according to resistance and there are generally two standards to watch out for.

The first is color-coding where the tolerance values of the resistor in question are displayed on the body of the component by the presence of four different colored bands. The first two bands highlight the primary digits of the resistance value, while the third band dictates the multiplying factor. Together, you will be able to calculate the total value of resistance which is also indicated by the fourth band. Use a resistance color code calculator to help you determine these values quickly and accurately.

The second standard used in measuring the resistance of a resistor is SMD codes. These codes are based on numerical values and are usually used when a resistor is too small to effectively display color coding on its body.

In order to select the right resistor for the right application, you need to begin by determining the level of resistance that your application requires. You will then need to calculate your power rating. Once you have these two values, you can then choose a resistor to match them.

It is always worthwhile to use a search engine specifically created for electrical engineers to aid you in your search for a resistor. These search engines allow you to compare the various resistors on offer from a broad array of manufacturers and with various resistance values. You will also be able to compare the costs of these resistors for sale online or in-store from several different distributors. Octopart is an excellent example of one of these search engines.

You now have the knowledge required to make a sound decision and to maximize the efficiency of your final product.

Mark Funk
Mark Funk is an experienced information security specialist who works with enterprises to mature and improve their enterprise security programs. Previously, he worked as a security news reporter.