Resistors

In previous lecture , we have already discussed that Resistors act to control the level of voltage and current in a circuit.

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element.

Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits

The resistor’s ability to reduce the current is called resistance and is measured in units of ohms (symbol: Ω).

Question:

Answer

Just by at looking the size of a resistor , we can not decide , which resistor has high ohmic value , and which resistor has lower ohmic value.

How ever one thing for sure is that , bigger the size of resistor is higher is the power rating

Colour Coding of Resistor

In most cases, the resistor is presented with colored rings (bands) around it. Each color corresponds to a digit.

The correspondence between the digits and the colors of the bands is named “the resistor color code”: This code is used to determine the value of a resistor or indicate its values

Resistors have standard colors for identification of the resistance value. In order, the colors are: black, brown, red, orange, yellow, green, blue, violet, gray, and white.

Hold the resistor with the gold or silver band to the right and read the resistor from the left to the right. Normally bands are usually “left justified” to reduce the likelihood of being miss-read

The first two bands provide significant figures of the codes . The third gives the multiplier · The fourth determines the tolerance

Find Color Code for

The Colors are Orange Blue Black , which gives us values of 36 ohm

Find Color Code for

The Colors are Yellow White Orange which gives us values of 49 K Ohm

Find Color Code for

The Colors are Red Red Red and Silver, which gives us the value of 2.2 K Ohm with 10 % tolerance