Lab 8-2 Basic Electrical Circuits

 

Requirement

Check

Created circuit

 

Added switch

 

Drawing of circuit

 

Measured voltage

 

Measured amps

 

Answered questions

 

Cleaned up station

 

 

 

Objective

The objective of this lab exercise is to demonstrate and define basic concepts and terminology related to the study and use of electricity. After completing this lab exercise, you will be able to:

7  _ Create a simple switched circuit.

7  _ Describe the relationship between voltage, amperage, ohms, and wattage.

7  _ Use a multimeter to measure voltage and amperage.

 

Materials Required

7  _ One 9-volt battery (AA is an acceptable substitute)

7  _ One multimeter (capable of measuring amps)

7  _ One incandescent light bulb rated at 12 volts

7  _ One switch

7  _ Three pieces of standard-grade electrical wire

7  _ Electrical tape to attach wires to the battery, if necessary

 

Lab Setup & Safety Tips

7  Each group will require a clean desktop area for building their switched circuit.

7  The instructor must demonstrate for each student group how to configure the multimeter to measure volts and amps.

 

ACTIVITY

Creating a circuit

  1. Attach one piece of wire to each lead on the light bulb.
  2. Attach one of the wires to the battery’s lead.
  3. Attach the second wire to the other battery lead.
  4. Observe the results. What happened?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. In the space provided below, draw a diagram demonstrating the flow of electricity in the circuit you have created. Be sure to note the direction of the current’s flow.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Adding a switch

1. Disconnect the wire from the negative side of the battery.

2. Attach the wire to an available lead on the switch.

3. Attach the third wire to the other switch lead and then attach it to the battery.

4. Observe how the switch manages the circuit. What happens?

 

 

 

 

 

 

Measuring voltage

1. Configure your multimeter to measure the voltage of your circuit.

2. Attach the +/- leads from your multimeter to the respective +/- sides of the light bulb.

3. Be sure that the switch is turned to the ON position.

4. Record the voltage of your circuit:

 

 

 

 

Measuring amps

1. Configure your multimeter to measure the amps of your circuit.

2. Disconnect the wire that is not currently attached to the switch.

3. Attach the respective +/- side of the multimeter to the battery lead that is not attached to any wires.

4. Attach the respective +/- side of the multimeter to the light bulb that is not attached to any wires.

5. Turn the switch to the ON position.

6. Record the amps found in your circuit:

 

 

 

 

Review Questions

 

Circle True or False.

1. Resistance is measured in ohms. True / False

2. A switch can act as a break in a circuit. True / False

3. AC is the acronym for ampere. True / False

4. A multimeter can measure only voltage. True / False

5. In a circuit, amps and volts are always the same amount when measured. True / False

6. Describe the difference in multimeter placement for measuring volts and amps.

 

 

Lab Notes

7  What does AC mean?—Alternating current (AC) is current that cycles back and forth rather than traveling in only one direction. Normally between 110 and 125 AC volts are supplied from a standard wall outlet.

7  What are amps?—Amps are units of measurement for electrical current. One volt across a resistance of one ohm will produce a flow of one amp.

7  What are volts?—A volt is a measure of electrical pressure differential. A computer power supply usually provides four separate voltages: +12 V, -12 V, +5 V, and -5 V.

7  What is wattage?—Wattage is a measure of the total amount of power that is needed to operate an electrical device.

7  What are ohms?— An ohm is the standard unit of measurement for electrical resistance. Resistors are rated in ohms.