A1 LT9 Flashcards
What precautions should be taken when using electrical measuring instruments?
Do not use resistance-measuring device on a live circuit
How should you select the meter range for a reading?
Top two-thirds of the scale
What should you not exceed when using a coil with an ohmmeter?
Current rating.
What type of scale is used when there are equal spaces between each division?
Linear scale
Why is it important to read the meter while looking straight at the pointer?
Accuracy
What should you do when finished with a meter?
Switch it off
What should you not exceed when using an ohmmeter?
Power rating of the meter.
What is the error introduced when looking at the meter from off to either side?
Parallax error
What should you switch a meter to if there is no OFF switch position?
Highest possible range
What should you switch a multimeter to for AC voltage measurements?
Highest possible AC voltage range
Why is it difficult to visually identify issues in an electric circuit?
Electricity cannot be seen
What should you avoid when using galvanometer-based meter movements?
Avoid placing near other magnetic fields
What are meters used for in relation to electricity?
Measure effects of electricity
What can happen if a stray magnetic field affects the instrument?
Inaccurate responses or damage
Why should you take great care with electrical meters?
Precision instruments, easily damaged
What type of meter should be used based on whether you are working with DC or AC?
Match the meter to the supply
Why are moving coil instruments particularly susceptible to vibration and sudden impact?
Delicate parts
What can happen if the meter is not used in the proper position?
Inaccurate readings
What should you do every time you change scales on an ohmmeter?
Zero the meter again
Why should you use the built-in holding device when transporting or storing the meter?
To retain moving parts
What are voltmeters used to measure?
Potential difference
How are some meters constructed to protect against parallax error?
With a small mirror just below the scale markings
Why is it important to test the voltmeter on a known source before and after using it?
To prevent faulty readings
Why is it crucial to make sure the voltmeter is on the appropriate range setting?
To ensure accurate readings
What is the purpose of performing meter readings in electricity?
Verify circuit concepts
Why should the current be OFF when using a resistance-measuring device?
To avoid damaging the ohmmeter
Why should an ammeter never be connected in parallel?
Forms a short circuit
Why is it important to observe the meter polarity when connecting it into the circuit?
To avoid damaging the meter
What must you observe when using an ohmmeter?
Never use on live circuits.
