Experiment 4: DC Circuits
BACKGROUND AND THEORY
The resistance R of a metallic conductor is defined by
R =
Voltage
Current =
V
I
(4.1)
where V is the potential difference applied between the endpoints of the conductor and I is 
the current flowing through the conductor.For a metallic conductor, such as a copper wire, the resistance R is a constant provided that 
the temperature of the wire stays essentially constant, that is R does not depend on I or V.
Units: V is measured in volts (V), I in Amperes (A) or milli-amperes (mA), and R in Ohms 
(?).PROCEDURE
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Part A: DC Circuit with One Resistor
1.We can test if a
material is ohmic or not by measuring the potential difference V across the material against 
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a current I that pass through it while keeping the temperature of the material constant.1: Example of Ohmic and Non-Ohmic Materials
Conductors obey Ohm's law and are called ohmic materials.Figure 4.