## Resistor:

It is the fundamental circuit component which use to oppose the flow of current or component or device or component designed to have a known value of** resistance.** Many types of resistors are available in the market. The main purpose of resistor us to limit the current (flow of **electron**) in a particular circuit. . Resistors come in a variety of forms and you can purchase them as your wise, or even some using terminals to the very small **surface mount components** used in many electronics circuits today.

A resistor is the one of the three fundamental passive circuit element and as such cannot deliver

**power or store energy**. Instead, resistors absorbed power that appears as heat (heater) and light (Light Emitting Diode). Power in a resistance is always positive regardless of voltage polarity and current direction. It just limits the current. In

**conductor**small value of resistance always present.

There are many different types of resistor. Even though they all resist current flow, their other parameters mean that some types are more suitable for particular applications than others.

## Types of resistor:

There are two types of the resistor are classified

- Linear Resistors
- Non-Linear Resistors

Here Linear resistors can be classified as

- Fixed Resistors, it can be classified as
- Carbon Composition Resistors
- Wire Wound Resistors
- Thin Film Resistors
- Thick Film Resistors

- Variable Resistors, it can be classified as,
- Potentiometers
- Rheostats
- Trimmers

## Power Dissipation in a resistor:

As we Know from ohm’s law, V is the input voltage and I is the **current** flowing through the resistor and R is the resistance circuit.

**Power** dissipation in the circuit

Here P is the power dissipation in the circuit. And the power rating normally, mentioned in Watts

## The power rating of a resistor:

When the resistor manufacturer design a resistor, all the resistor has the power ratings which is the maximum power that resistor can absorb the power with safe operating limit, beyond that the resistance might be damaged.

Example:

2 Watts resistor means; it consumes 2 watts per hour.

## Different resistance connection:

You can modify or change the total resistance value of the circuit by adding different value resistor in series or parallel with the circuit. Let see how series or parallel resistor connection changes the equivalent **resistance** of the circuit.

### Resistor series connection:

Refer the diagram, here the resistor R1, R2 and R3 is connected in series, Requ is the equivalent resistance of the circuit and the V1, V2, and V3 are the** voltage** drop across the resistor, V is the input voltage and the Current I is flowing through all the resistor. apply Kirchhoff voltage rule.

Here the equivalent resistance of the circuit is equal to Sum of all individual resistance of the circuit which all connected in series each other. You can add an unlimited number of connection in the same way and you can calculate equivalent resistance in the same way.

### The resistor in parallel Connection:

Refer the diagram, here the resistor R1, R2 and R3 is connected in parallel, Requ is the equivalent resistance or sum of all resistance of the circuit and the V is the voltage drop across the resistor, V is the input voltage and the Current I1, I2 and I3 are flowing through the individual the resistor R1, R2 and R3. I is the circuit total current, apply Kirchhoff current rule.

Note: Voltage in a parallel circuit is equal to the applied source voltage. Hence V input voltage is equal to the Voltage across the all individual resistor.

Reciprocal of equivalent resistance is equal to a sum of reciprocal of an individual resistance value of the circuit.