2. Register Digital Multimeter Usage Click Register to begin the course

3. Next This lesson is for diagnosing a inoperative light bulb

4. The first step is to check the source voltage Click on the Multimeter below to see how to set up the meter

5. In this lesson, you will learn how to set up a Digital Multimeter (DMM) to perform various measurements Click on the audio icon to learn more Digital Multimeter (DMM) Usage DC Voltage Common Volt/Ohm DC Voltage up to 1000 volts Parallel Power must be turned on How is the rotary switch positioned? In which input jack is the black lead installed? In which input jack is the red lead installed? Based on the previous questions, what is the meter set up to measure? How does this meter need to be connected to a circuit or component (in series or in parallel)? Should the power in the circuit be on or off to perform this measurement? Next

6. Check Battery Voltage #1 The red meter lead is placed on the positive terminal of the battery Click on the Meter to place the red lead The black meter lead is placed on the negative terminal of the battery Click on the Meter to place the black lead 12 Volts at the battery indicates a good battery source Proceed to next step in diagnosis < 5 Volts at the battery indicates a bad battery Fix: Charge or replace battery Next

7. Check for Voltage at the Switch #2 The red meter lead is placed on the side of the switch closest to the battery Click on the Meter to place the red lead The black meter lead is placed on the negative terminal of the battery Click on the Meter to place the black lead 12 Volts at switch indicates a good wire between positive and switch Proceed to next step in diagnosis < 5 Volts at the switch indicates a bad wire from positive terminal of battery to switch Fix: Replace Wire from positive terminal of battery to switch Next

8. Check for Voltage at the Switch #3 The red meter lead is placed on the other side of the switch Click on the Meter to place the red lead The black meter lead is placed on the negative terminal of the battery Click on the Meter to place the black lead 12 Volts at switch indicates a good switch Proceed to next step in diagnosis < 5 Volts at the switch indicates a bad Switch Fix: Replace switch Next

9. Check for Voltage at the Bulb #4 The red meter lead is placed at the bulb side closest to the battery Click on the Meter to place the red lead The black meter lead is placed on the negative terminal of the battery Click on the Meter to place the black lead 12 Volts at switch indicates a good wire between switch and bulb Proceed to next step in diagnosis < 5 Volts at the bulb indicates a bad wire between switch and bulb Fix: Replace wire between switch and bulb Next

10. Check for Voltage after the Bulb The red meter lead is placed on the other side of the bulb Click on the Meter to place the red lead The black meter lead is placed on the negative terminal of the battery Click on the Meter to place the black lead 12 Volts at the bulb indicates a good bulb and a bad ground To verify bad ground do a resistance check on the ground. Click next to see the meter set up for Ohms 0 Volts at the bulb indicates a good ground and a bad bulb Fix: Replace the bulb Next

11. In this lesson, you will learn how to set up a Digital Multimeter (DMM) to perform various measurements Click on the audio icon to learn more Digital Multimeter (DMM) Usage Ohms Common Volt/Ohm Resistance displayed in Ohms Parallel Power must be turned off How is the rotary switch positioned? In which input jack is the black lead installed? In which input jack is the red lead installed? Based on the previous questions, what is the meter set up to measure? How does this meter need to be connected to a circuit or component (in series or in parallel)? Should the power in the circuit be on or off to perform this measurement? Next

12. Check the resistance of the ground wire #5 The red meter lead is placed on the known good ground Click on the Meter to place the red lead The black meter lead is placed on the ground circuit for the bulb Click on the Meter to place the black lead Below 5 Ω indicates a good ground Above 5 Ω indicates a bad ground Fix: Replace the Ground Wire Disconnect the Power Source Click on the battery to Disconnect the Power Next

13. Review What does the reading on the meter indicate? Make your selection Below The Battery is Good The Battery is Bad 0 V

14. Correct. < 5 Volts at the battery indicates a bad battery 0 V Next

15. Sorry you are incorrect. < 5 Volts at the battery indicates a bad battery. This battery would need to be charged or replaced 0 V Review

16. What does the reading on the meter indicate? Make your selection Below Good Wire Between Positive and Switch Bad Wire Between Positive and Switch

17. Correct 12 V at this point indicates a good wire from battery positive to switch Next

18. Sorry Incorrect 12 V at this point indicates a good wire from battery positive to switch Review

19. What does the reading on the meter indicate? Make your selection Below 0 V Bad Switch Good Switch

20. Correct < 5 Volts at the switch indicates a bad Switch 0 V Next

21. Sorry Incorrect < 5 Volts at the switch indicates a bad Switch 0 V Review

22. What does the reading on the meter indicate? Make your selection Below a good wire between switch and bulb a bad wire between switch and bulb

23. Correct 12 V indicates a good wire between switch and bulb Next

24. Sorry Incorrect 12 V indicates a good wire between switch and bulb Review

25. What does the reading on the meter indicate? Make your selection below A Good Bulb and a bad ground A bad Bulb and a good ground 0 V

26. Correct <5 Volts indicates a bad Bulb and a good ground 0 V Next

27. Sorry Incorrect <5 Volts indicates a bad Bulb and a good ground 0 V Review

28. A good Ground A Bad Ground What does the reading on the meter indicate? Make your selection below 3 Ω

29. Correct < 5 Ω indicates a Good Ground 3 Ω Next

30. Sorry Incorrect < 5 Ω indicates a Good Ground 3 Ω Review

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