Rosewill Computer Case 422 Informacje Techniczne Pobierz pdf (Strona 92)

175

Exercises

Disassembly

and Power

4. If the meter has leads that attach, attach the black meter lead to the appropriate port col-

ored as a black port or has the COM labeling. Attach the red meter lead to the positive or

port marked with a plus sign ( + ).

5. Turn on the meter. Set the meter so that it is measuring VDC (DC voltage). This may

involve manually rotating a dial and/or pushing a button. Note that some meters can

autodetect the setting, but most involve configuration.

Document what you did to configure the meter for VDC.

What indication, if any, did the meter show in the meter window that VDC is being

measured?

6. Hold the meter leads so that the black lead is in your left hand and the right lead is in

your right hand. Ensure your hands are behind the protective ring on the meter handle.

Refer to Figure 4.16 if you are unsure.

7. Place the black meter lead to the negative side (left side or left connector). Also touch the

red meter lead to the positive side (right side or right connector) of the battery. Make a

note of the meter reading.

DC volts:

Based on your findings, is the battery good (usable in an electronic device)?

8. Now reverse the meter leads—place the black lead to the positive side and the red lead to

the negative side. Record your findings.

DC volts:

What was different from the original meter reading?

9. Perform this voltage check on any other batteries given to you by the instructor or lab

assistant.

10. Straighten a paperclip or obtain a wire. Place the paperclip or wire on a flat surface.

11. Change the meter so that it reads ohms. This is normally shown by the omega symbol (Ω).

While having the meter leads up in the air (not touching each other), what does the

meter display?

12. Touch the meter leads together to make a complete circuit or path.

What does the meter display now?

13. Touch one meter lead to one end of the paperclip or wire, and touch the other meter lead

to the opposite paperclip or wire end. Sometimes it is easier to just lay the meter lead on

top of the wire close to the end.

What is the meter reading?

14. Some meters have the ability to make a sound when a wire is good. This is frequently

shown on your meter as a sound wave ( ). If your meter has this ability, configure the

meter and redo the test. You can see how much easier this would be than trying to hold

your meter leads straight and watch the meter.

Instructor initials: ______________

15. Power off the meter. Disconnect the leads as necessary. Return all parts to the appropriate

location.

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