Purpose
The experiment was done to learn the basic concepts of Direct Current (DC) electric
circuits by measuring voltages and currents in some simple circuits.
Apparatus
Voltmeter, Wire-Coil Resistor, Slide, Double-pole Single-Throw Switch, Input (3 volts
DC),
Ammeter, Multimeter (Ohm Meter), Carbon resistor (2), Light bulb (2), red and black
wires.
Theory
Direct circuit (DC) is the constant flow of electric charge. The unit of current (I) is Amp,
which is c/s. Voltage (V) is ability to cause current and resistance R is measured in unit, ohm(Ω).
Ohm’s law is V=IR. When V and I are plotted, the slope of the graph is R, resistance. In series
connection, R
eff
= R
1
+ R
2,
where in parallel connection, (1/ R
eff
) =(1/ R
1
) +(1/ R
2
).
Procedure
For the first experiment, a voltage source was connected using the diagram given. Then,
the voltage change was observed whether it changes linearly or not. Then, using the voltage
source connected, a resistor, and an ammeter, the Ohm’s law was examined. Voltage and the
current were measured and using the data, resistance was calculated for eight different voltages.
Then, V and I were plotted and R was obtained from the slope of the graph. The value of R was
also measured using the Multimeter as an Ohm meter. And the color code was also used to figure
out the theoretical R value. Then, the carbon resistor was replaced with one light bulb. The
brightness of the bulb and the current was observed.