Resistance & Its Types

Information about Electronics:

                     In this blog, I will be fully explained about resistance and its types.

What is resistance;

Resistance is the measure of opposition to electric current. A short circuit is an electric circuit offering little or no resistance to the flow of electrons. Short circuits are dangerous with high voltage power sources because the high currents encountered can cause large amounts of heat energy to be released.

How to measure resistance:

The resistance value, tolerance, and wattage rating are generally printed onto the body of the resistor as numbers or letters when the resistors body is big enough to read the print, such as large power resistors. But when the resistor is small such as a 1/4 watt carbon or film type, these specifications must be shown in some other manner as the print would be too small to read.

Calculating Resistor Values

The Resistor Colour Code system is all well and good but we need to understand how to apply it in order to get the correct value of the resistor. The “left-hand” or the most significant coloured band is the band which is nearest to a connecting lead with the colour coded bands being read from left-to-right as follows:

Digit, Digit, Multiplier = Colour, Colour x 10 colour  in Ohm’s (Ω)

For example, a resistor has the following coloured markings;

Yellow Violet Red = 4 7 2 = 4 7 x 102 = 4700Ω or 4k7 Ohm.

these sayings are often very crude but never the less effective for remembering the resistor colours. Here are just a few of the more “cleaner” versions but many more exist:

Bad Booze Rots Our Young Guts But Vodka Goes Well

Bad Boys Ring Our Young Girls But Vicky Goes Without

Bad Boys Ring Our Young Girls But Vicky Gives Willingly — Get Some Now (This one is only slightly better because it includes the tolerance bands of Gold, Silver, and None).

Different Types of Resistors;

There are different types of resistors. Some of these are described below.

·        Wire wound resistors

·        Metal film resistors

·        Thick film and Thin film resistors

·        Network and Surface Mount Resistors

·        Variable Resistors

·        Special resistors

Wire wound resistors;

A wire wound resistor is an electrical passive component that limits current. The resistive element exists out of an insulated metallic wire that is winded around a core of non-conductive material. ... They can be produced very accurate, and have excellent properties for low resistance values and high power ratings.

Symbol of wire wound resistance :

Metal film resistor;

Metal film resistors have a thin metal layer as resistive element on a non-conducting body. They are amongst the most common types of axial resistors. Other film type resistors are carbon film and thick and thin film resistors. In most literature referrals to metal film, usually it is a cylindrical axial resistor.

           

Thick film and Thin film resistors;

Thin film has a thickness in the order of 0.1 micrometer or smaller, while thick film is around thousands time thicker. However, the main difference is method the resistive film is applied onto the substrate. Thin film resistors have a metallic film that is vacuum deposited on an insulating substrate.

Network and surface mount resistor;

Resistor networks also known as resistor arrays feature multiple resistors connected together in a circuit pattern. They primarily act as a voltage divider, which split the voltage in a circuit to smaller amounts.

Symbol ;

Variable resistor;

Variable resistors are resistors of which the resistance value can be adjusted, the most common types are a potentiometer, rheostat or digital resistor.

Symbol ;

Special resistors ;

Resistors. Resistors restrict or limit the flow of current in a circuit. The ability of a material or component to resist current flow is measured in ohms. ... variable resistors. special resistors, such as thermistors and light-dependent resistors (LDRs)