Measuring Voltage, Current and
Resistance Lab Summary
Voltage (symbol = V)
 the
force which pushes electrons through a circuit
resulting in electrical current flow.
 Magnitude expressed in units of Volts (V)
 Named after Count Alessandro Volta who invented first
voltaic cell
 Measured using voltmeter
or multimeter (DMM)
 Higher voltage means stronger force
Measuring Voltage, Current and
Resistance Lab Summary
Current (symbol = I)
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The amount of electrons flowing past a point in a conductor in a
certain amount of time. Current is considered a rate since
associated with time.
More electrons flowing means greater current
Magnitude measured in units = amperes (A)
Named after Andre Ampere who discovered that a magnetic
field forms around a wire when a current passes through it
(theory of electromagnetism)
Measured using an ammeter
or multimeter (DMM)
1A=6.24x1018 e2 types of current:
1.
2.
Alternating (AC): changes direction/polarity many times per sec
Direct (DC): flows in 1 direction only
Measuring Voltage, Current and
Resistance Lab Summary
Resistance
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Opposition to the flow of current
Each component in a circuit creates resistance but some more than others. Resistance results
in heat, light or motion given off
Resistors are components designed especially to resist (decrease amount of current going
from one component to another) Why?
Brown,gold,black,black
Orange,orange,orange,gold
Green,blue,brown,gold
Black,green,yellow,purple
Black,green,blue,black
Brown,green,red,green
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Magnitude measured in ohms (Ω)
Named after Georg Simon Ohm who discovered
relationship between voltage, current and resistance….
known as Ohm’s Law:
R=V
I
Activities
OLL#10: Complete Problems 1-2,5-6,9-10 at the
link below:
http://www.wisconline.com/objects/index_tj.asp?objID=dce11904
Note: Use GFS and write out your solution on a piece
of paper first . Then check your answer on the site
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Activities cont.
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Activity:
a)Find the resistance of each of the 6 resistors on
the previous slide. Use the colour chart to find your
answers.
b) Find the resistance of each of the 4 different
resistors in the container at your table