1- To determine the value of a selection of resistors using three different methods:

Using the color codes (to give the nominal value)

Using the digital Ohmmeter.

Using Ohm's Law.

2- To determine qualitatively the effect of increased power dissipation on a carbon resistor.

a.

b.

C.

Apparatus:

DC Power Supply

Digital Multimeter

Resistor: 100Ω.470Ω,1 ΚΩ.

Theory:

1- The basic relationship between voltage, current, and resistance is determined by Ohm's law:

(1)

Where:

V=IR

V = Voltage across the resistor (in Volts)

I = Current through the resistor (in Amperes)

R = Resistance of the resistor (in Ohms)

2- Given any resistor, its resistance can be found by one of the three methods:

a- Using the color codes. This value is called the nominal value, and it is only

approximate.

b- Direct measurement using an Ohmmeter.

c- Measuring the voltage across the resistor and the current through the resistor; then

applying Ohm's law.

3- The product of the voltage across a resistor and the current through the resistor give power