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
Fig: 1