What is a resistor?

A resistor is an electrical component that limits or regulates the flow of electrical current in an electronic circuit. Resistors can also be used to provide a specific voltage for an active device such as a transistor.

The resistance is measured in ohms (Ω). An ohm is the resistance that occurs when a current of one ampere (A) passes through a resistor with a one-volt (V) drop across its terminals. The current is proportional to the voltage across the terminal ends. This ratio is represented by Ohm’s law: $R=\frac{V}{I}$

Resistor Symbol

here are two main circuit symbols used for resistors. The oldest one is still widely used in North America and consists of a jagged line representing the wire used in a resistor.

The other resistor circuit symbol is a small rectangle, and this is often termed the international resistor symbol and it is more widely used in Europe and Asia.

Resistor Symbols

Types of resistors

Resistors come in two main types:

1. Fixed Resistors: These are the most common resistors used in electronic circuits to set specific conditions. Their values are chosen during the circuit design and don't usually need to be changed afterward.
2. Variable Resistors: These resistors have a slider that can tap onto the main resistor element, creating three connections. When all three connections are used, it acts as a variable potential divider. By connecting to the slider and one end, you get a resistor with variable resistance.

For more detailed information about each type, you can search for them on the Internet.