Electrical Circuits Pre-LabElectrical Circuits Pre-Lab

Constructing and Analyzing Constructing and Analyzing

A Simple Series CircuitA Simple Series Circuit

SafetySafety

Only turn on power after circuit is connectedOnly turn on power after circuit is connected

No loose long sleeves, rings, or braceletsNo loose long sleeves, rings, or bracelets

No food or drinkNo food or drink

Keep miscellaneous objects away from Keep miscellaneous objects away from circuitcircuit

Reverse terminal connections if meter Reverse terminal connections if meter needle moves backwardneedle moves backward

link to electric shock jacket...

MaterialsMaterials

Voltmeter

Voltage Source

Resistors Breadboard

+ =Ammeter

Finding the value of the unknown resistor Finding the value of the unknown resistor using Ohm’s Lawusing Ohm’s Law

Voltage (V) Voltage (V) is measured inis measured in Volts (V) Volts (V) Current (I) Current (I) is measured inis measured in Amperes (A) Amperes (A)

Resistance (R) Resistance (R) is measured inis measured in Ohms (Ω) Ohms (Ω)

Data to CollectData to Collect

2 Resistors connected in series2 Resistors connected in series Measuring resistance, current, and voltageMeasuring resistance, current, and voltage Current ReadingsCurrent Readings

Use the readings from your ammeter to fill out the tableUse the readings from your ammeter to fill out the table

  Total Current from Total Current from Ammeter Ammeter (I(ITT))(amps)(amps)  

Current in Unknown Current in Unknown Resistor Resistor (I(I11))(amps)(amps)  

  Current in30 ohm Current in30 ohm Resistor Resistor (I(I22))(amps)(amps)

3030 Ω

Voltage ReadingsVoltage Readings Use the readings from your voltmeter to fill out the tableUse the readings from your voltmeter to fill out the table

Measured Voltage in Measured Voltage in Unknown Resistor Unknown Resistor (V(VRR11))  (volts)(volts)

Measured Voltage in 30 Measured Voltage in 30 ohm Resistor ohm Resistor (V(VRR22) (volts)) (volts)

Total Voltage from Total Voltage from Source Source (V(VTT) (volts) ) (volts)

Data to Collect (cont’d)Data to Collect (cont’d)

CalculationsCalculations

Finding Total Resistance using 2 methodsFinding Total Resistance using 2 methods

Method 1:Method 1:

Method 2:Method 2:

Voltage (V) is measured in Volts (V)Current (I) is measured in Amperes (A)Resistance (R) is measured in Ohms (Ω)

Resistance (R) is measured in Ohms (Ω)

Thought Provoking QuestionsThought Provoking Questions

Similar to lab writeupSimilar to lab writeup If you added another resistor to this circuit, If you added another resistor to this circuit,

what effect would it have on the size of the what effect would it have on the size of the total current? total current?

Use a relevant equation to explainUse a relevant equation to explain If the total voltage supplied to the circuit If the total voltage supplied to the circuit

remained unchanged, how much resistance remained unchanged, how much resistance must be added/subtracted to achieve a must be added/subtracted to achieve a greater/lesser total current? greater/lesser total current?

Lab GroupsLab GroupsDivision of laborDivision of labor

Assign a group member to Assign a group member to one of the following roles:one of the following roles:

Recorder (Records data) Recorder (Records data) Reader (Reads instructions Reader (Reads instructions

and checks off each and checks off each procedure upon completion)procedure upon completion)

Circuit Constructor and Circuit Constructor and Meter ReaderMeter Reader

Switch jobs 3 times during Switch jobs 3 times during lab (V, I, lab (V, I, Ω)

Initial any data that you recorded

Safety Safety RevisitedRevisited

Only turn on power after circuit is connectedOnly turn on power after circuit is connected

No loose long sleeves, rings, or braceletsNo loose long sleeves, rings, or bracelets

No food or drinkNo food or drink

Keep miscellaneous objects away from Keep miscellaneous objects away from circuitcircuit

Reverse terminal connections if meter Reverse terminal connections if meter needle moves backwardneedle moves backward