Resistors

Meaning behind resistors!

a device having a designed resistance to the passage of an electric current.

Purpose: to create specified values of current and voltage in a circuit.

UNITS!

For measuring resistance is the OHM

Resistor Markings

Resistance value is marked on the resistor body. Most resistors have 4 bands.

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The first two bands provide the numbers for the resistance and the third band provides the number of zeros. The fourth band indicates the tolerance.

Training Video: "Resistor Color Codes" | McNaudio Media Solutions LLC (2009)

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Example of a circuit containing three resistors connected in parallel

Resistors in Parallel Circuits

Resistors can be connected such that they branch out from a single point (known as a node), and join up again somewhere else in the circuit.

Which is known as the parallel connection.

Resistors In Parallel

Calculate

• R1+R2+R3=Rtotal

Resistors in Series

• Resistors can be connected in series; that is, the current flows through them one after another.

Resistor Dissipation

If the flow of current through a resistor increases, it heats up, and if the temperature exceeds a certain critical value, it can be damaged. The wattage rating of a resistor is the power it can dissipate over a long period of time.

Wattage

Most commonly used resistors in electronic circuits have a wattage rating of 1/2W or 1/4W