ohmslaw.ppt
TRANSCRIPT
Unit 5, Day 9: Ohm’s Law Objective Question
How are voltage, current, and resistance calculated?
Opener
1. Review: define series circuit.
2. Review: define parallel circuit.
3. Review: what is resistance?
4. What is the relationship between resistance and current?
5. If the voltage in a circuit increases, what will happen to the current?
Voltage and CurrentStreamsrepresen
tCurrent
Snowcaprepresen
tsVoltage
Ohm’s Law
Using a MultimeterMeasuring
CurrentMeasuring
VoltageMeasuring Resistance
DefinitionThe flow of electricity
Electric potential energy
How difficult it is for current
to flow
Unit Amps (A) Volts (V) Ohms (Ω)
Black Wire COM COM COM
Red Wire 10A Input Input
Dial A V Ω
Setting DC DC -
Location of Probes
Across the open switch
On either side of battery or
bulb
Either side of resistor (not in
circuit)
Mystery Resistors Lab Build a simple circuit, using the
different colored resistors in place of a light bulb. Use only one resistor at a time. Your circuit needs a switch.
Measure current and voltage.
Calculate the resistance using Ohm’s Law.
Measure the resistance using the multimeter.
Resistor Current (A)Voltage Across
Resistor (V)
Calculated Resistance
(Ω)
Measured Resistance
(Ω)
Red
Green
Blue
Mystery Resistors: Analysis Questions
1. Did the measured resistance and calculated resistance match? Why or why not?
2. Which color resistor was it the most difficult for electricity to flow through? Use the word “resistance” to explain why.
3. Which color did the electricity move through most easily? Use the word “resistance” to explain why.
4. Relationship statement: as voltage increases, the current _________.
5. What is the relationship between resistance and current?