What are the precautions taken while using a dc voltmeter and dc ammeter?
Answers
PRECAUTIONS WHEN USING A VOLTMETER & AMMETERS
Observe the correct polarity.
Wrong polarity causes the meter to deflect against the mechanical stop and this may damage the pointer.
Place the voltmeter across the circuit or component whose voltage is to be measured.
When using a multi range voltmeter, always use the highest voltage range and then decrease the range until a good up-scale reading is obtained.
Always be aware of the loading effect.
The effect can be minimized by using as high a voltage range as possible. The precision of measurement decreases if the indication is at the end of the scale.
PRECAUTIONS WHILE USING AN AMMETER
Never connect an Ammter across a source of emf.
Because of its low resistance it would draw damaging high current and destroy the delicate movement.
Always connect an ammeter in series with a load capable of limiting the current.
Observe the correct polarity.
Reverse polarity causes the meter to deflect against the mechanical stop and this may damage the pointer.
When using a multi range meter, first use the highest current range, the decrease the current rage until substantial deflection is obtained.
To increase accuracy of the observation, use the range that will give a reading as near to full-scale as possible.
Answer:
The precautions which we need to use are listed below.
Explanation:
When using ammeters, you should take these precautions:
Ammeters must be wired into circuits in series.
1. Always use a series resistance when connecting ammeters across an emf source.
To stop current from flowing through the meter, this is required.
2. The meter should be attached in accordance with its polarity after being observed. The meter pointer could be harmed by reverse polarity.
3. When using a multirange ammeter, start with the highest current range and work your way down until you get a good upscale reading.
When utilizing voltmeters, precautions should be taken:
1. Because the Voltmeter has a very high resistance, care should be given when connecting it to ensure that it is connected across (parallel) the circuit or component.
2. Connections should be formed in accordance with observations of polarity.
3. When using a voltmeter, the highest range should be utilized initially, followed by a decrease in range.
4. Using high sensitivity can help to decrease the loading impact.
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