Electric current is simply the motion of electrons from one place to another through a wire. The more electrons that are flowing, the higher the current.
Resistors have an apt name: They “resist” the electrical current going through them. You can think of resistors as “brakes” for electrons. By controlling the electrons going through a resistor, you can make a circuit do different things.
Resistors may be the primary building block of circuits, so you see them quite a bit in electronics projects. Here are some of the things you can use them for:
Types of Resistors
Resistors can come up in various types and sizes:
Resistors with a fixed ohmic value are (Obviously!) called fixed resisters. They are the most common and they come in different sizes depending on the power handling. Usually the bigger the resister in physical size the more power it can handle.
Various shapes of Fixed Resistors
Fixed Resistor Symbol
Variable resistors (Potentiometer)
These resistors come in a round shape housing with a dial that can be changed manually. The value of the resistor can be increased or decreased by turning the dial clock or counter clock wise. The most common application is the volume control of a speaker. Potentiometers come in two types:
How Variable Resistor Works
Variable resistor Symbol
Resistors Colour Code
Every resistor has its value either written in plain English or coded using colour codes. Colours on the resistor can be interpreted using the following table:
How I memorized the colour code sequence
I always had trouble remembering the sequence of colours , once a friend of mine gave me a phrase (Translators! please note that this is valid only in English) to help me recall the colours sequence: