What Is Resistor?




If you are new in electronics, you may ask what is resistor? There are two types of main classifications of resistors: fixed and the variable type. The fixed resistor have a static ohms value which mean it can't be vary, the variable type ohms value can be change or vary. A resistor is a passive component that opposes the flow of electrical current through it and the resistance is the measure of component's opposition to the flow of current.

Resistors are used extensively in electronic equipment. The basic unit of measurement is ohm which is the resistance that allows 1 Ampere of current to flow through it when 1 Volt is applied across it (Ohm's Law). Resistance is also expressed in Kilo-ohms, Mega-ohms, Milli-ohms and etc with 1 Mohm=1000k-ohm=1000000ohm=1000000000m-ohm.

There are many types of fixed resistors such as the carbon composition resistors, film resistors, wirewound resistors and so on. If several resistors are manufactured together in a single package, usually we called an R-pack. R-packs are made with several resistor leads in a single line, called a single inline package (SIP), or in a package with two rows of inline pins called a DIP, for dual inline package. Resistors also can be made into small, flat, rectangular component with two flat metals tabs are called surface mount technology (SMT).

wirewound resistor

A Wirewound Resistor

Quite often when a resistor fail they either increase in value or open circuit which mean the internal element have open up or break or even burnt. Resistor rarely fail by itself, usually another components that is ahead of the resistor circuit or connected together with the resistor that has developed a short circuit. Overheating may also make a resistor to increase in value or open. Sometimes the resistors colour code may changed into another colour or just fade away.

I've seen a resistor colour band suppose to be yellow colour but it turned out to be orange! There are many ways to check a resistor but somehow i have some proven methods to guide you on how to accurately check a resistor whether on board or off board. In this what is resistor web page i won't be explaining in details on how resistor work and how to test it, however you can always visit the testing resistor page in this website.